Antonym of "recommend"

What's the antonym of recommend? For example:

I recommend that item!

I tried to use unrecommend, but the spell-checker throws an error and it sounds stupid as well!

I would suggest “advise against.”

M-W dictionary lists no antonyms.

Dictionary.com lists: disapprove, discourage, dissuade but I don't think those really fit as direct antonyms.

Usually in my experience you'd say recommend against.

---Update to add--- As FumbleFingers mentioned in a comment, advise against is an equally valid alternative (and seemingly more popular in British English, as this NGram would suggest).

Strictly speaking, discommend is the antonym, although it doesn't work in all contexts, and has become nearly obsolete.

I agree with @breen that advise against is the modern antonym phrase.

In technical computer manuals we use the word "deprecate".