Meaning of "easy" in "easy on the eye/ear"

Easy on the eye/s

• Also,easy to look at. Attractive, beautiful, as in That model is definitely easy on the eyes. ; c. 1900 .

(AHD)

Easy on the ear/s:

• To have a pleasant and enjoyable sound. I find classical music to be very easy on the ear. After months of lessons, your sister's piano playing is finally easy on the ear.

Though the meaning of the above expressions is intuitive, you would not say that the model is easy or that classical music is easy without being easily misunderstood.

So what usage does "easy" in the above expression refer to? did "easy" at the beginning of the 20th century have a different connotation? Was it an AmE expression originally?

The phrases 'easy on the eye/s' and 'easy on the ear/s' are idioms. Idioms must have two properties:

(1) they are in relatively common use (don't ask how common), informed use of course and

(2) there must be some peculiarity about the expression – unusual syntax, an unusual sense of a word, an unusual interpretation for the whole string, or a mix of these. Often, there is a different meaning than one would normally identify ('kick the bucket' = 'die'). Such idioms are opaque.

Here, 'easy on the eyes' is a parallel construction to 'hard on the knees' say. The idiom is reasonably transparent (OP uses the word 'intuitive'), and so common that AHD say includes the sense of 'easy' involved:

easy adj. ... 4a Affording comfort or relief [/pleasure; not causing any pain at all]; soothing: soft light that was easy on the eyes.

It's probably best to treat 'easy on the eye/ear...' as a single idiom, but the metaphorical use of 'on' ('This jogging is so hard [ie causes excessive wear and tear, pain not pleasure] on the knees' / 'Don't be so hard on him'), implying imposition, is more general.

Tracing the etymology of AHD sense 4a for 'easy' probably equates to finding the first occurrence of 'easy on the eye/s'. The phrase was probably not used much before 1920, if these Google Ngrams accurately portray the situation.

The sense occurs elsewhere: 'This wine is very easy to drink.' This Ngram again supports the 1920s date for the increase in use of this sense of 'easy'.

It refers to the viewer! Because a beautiful model is 'easy to look at' so she is 'easy on your eyes' - ie, your eyes have no resistance to seeing her! It is 'easy to look' - because it is a pleasure! The person having an easy time - is you - not the model! It is no reflection on her - it is talking about your experience in observing her.

If she were ugly, and you needed to look at her, you'd have to work at it, wouldn't you? Because it would then not be a pleasure to see her. It would take effort - and would not then be - easy - for you.

Similarly, 'easy on the ears' means that the listener, ie you, would have no resistance to listening - as it is easy to listen - because it is a beautiful sound. So it is you having an easy time, as the listener - and no reflection on anyone else.

Yes, it is of US origin. It is an idiom deriving from OED sense 9 of the word easy - conducive to ease or convenience, as in easy chair. Sense 9c makes specific reference to women's looks, but in our less gendered society I see no reason why it should not apply to males.

9c. In phrases easy to look at, easy on the eye(s), affording pleasure to the beholder; esp. of women: comely, beautiful. colloq. (orig. U.S.). Also in various combinations, as easy-to-make, easy-to-operate, easy-to-use, easy-to-wear, etc.

1902 G. Ade Girl Proposition 141 He put his Tag on a blonde Canary 17 Years of Age who spelled Sure with an H and had from 7 to 9 Thoughts every 24 Hours. But she was very Easy to Look at.

1922 P. G. Wodehouse Clicking of Cuthbert x. 253 Her Highness is the easiest thing to look at these eyes have ever seen.

1937 C. Beaton Diary 3 June in Wandering Years (1961) 310 A pliable, easy-to-pose subject.

1937 Punch 8 Sept. 260/1 The same incorrigibly cheerful creature, very easy to look at, very pleasant to listen to.

1938 Amer. Speech 13 205 [The dictionary] is a substantial compilation, easy on the eyes, comparatively rich in idiomatic expressions.

1939 Vogue's Cookery Bk. i. 15 This is an easy-to-make soup for a hot day.

1943 D. E. Stevenson Two Mrs. Abbotts v. 35 Miss Walters was certainly easy on the eye.

1949 Consumer Reports Feb. 68/2 Many prospective purchasers want an easy-to-operate device.

1951 in M. McLuhan Mech. Bride 153/1 The same easy-to-follow lessons.

1958 Oxf. Mail 1 July 6/5 One of the good Westerns, easy on the eye and mind, and pretty tough on the pulses.

1959 Times 9 Mar. Suppl. p. x/3 Easy-to-serve packed foods.

1959 News Chron. 10 Aug. 6/5 This hat has the soft easy-to-wear line.

1959 Woman's Own 20 June 52/1 (advt.) The only home perm lotion in a tube with its own easy-to-use applicator-tip.

1960 Farmer & Stockbreeder 15 Mar. 122/1 This tough, easy-to-use, real wood building panel.

1960 Guardian 25 Apr. 4/1 Easy-to-follow recipes.

It's an idiom, with a slightly ironic tone. In both cases easy can be seen as an adverb modifying the process of looking/listening, rather than an adjective applying to the actual subject.

Easy here means "not difficult", with the idea that unattractive things are "difficult to look at", and discordant music is "difficult to listen to".

So, "easy on the eye" means "not difficult or unpleasant to look at", and "easy on the ear" means "not difficult or unpleasant to listen to".

So, if someone says of a woman "she is easy on the eye", they mean "It's enjoyable to look at her."