Very unusual meaning of "abortion"

Interesting :) But you can imagine that monstrosity is an extrapolation of the primary baby, miscarriage, blood and death definition. You actually can use Ngrams for this by searching for the term along with an appropriate adverb. In this case, I made an educated guess and searched for something along the lines of hideous abortion, ugly abortion and similar. As you have noted, the frequency of usage has petered out in the last few decades, albeit, not down to zero :) The graph also indicates that it was still being used with relative regularity in the '50s.

A few examples excerpted from the results:

From A sack of shakings by Frank Thomas Bullen, 1901:

She was everything that the Harbinger was not — an ugly abortion that the sea hated. When I first saw her (after I had shipped), I asked the cook whether she wasn't a razeed steamboat — I had almost said an adapted loco-boiler.

From The French Revolution: The Bastille by Thomas Carlyle, 1911:

Miserable man ! thou " hast done evil as thou couldst " : thy whole existence seems one hideous abortion and mistake of Nature ; the use and meaning of thee not yet known.

and via Wiktionary, from Pictures of Italy, Chapter 10, by Charles Dickens, 1846:

Insomuch that I do honestly believe, there can be no place in the world, where such intolerable abortions, begotten of the sculptor’s chisel, are to be found in such profusion, as in Rome.

Coleopterist’s etymological hunch is correct: abortion comes from Latin meaning to terminate a pregnancy by accident (to miscarry) or by intent (in which more restricted sense abortion seems increasingly to be used).

My inclination would be to assume that Greene knew his craft well enough to pick his words wisely. In addition to the sources coleopterist cites, you can find a contemporary review of Frankenstein describing the monster as “an abortion and an anomaly”.

A quotation from The Godfather: Part II gives a likely idea of how this metaphorical extension of meaning would have arisen. “Just like our marriage is an abortion. Something that’s unholy and evil.”

I have certainly heard the term used that way "in the wild". I had a co-worker who used to use it to characterize any badly-conceived (pun half-intended, I think) corporate policy.

In the USA at least, I think the word is so heavily and emotionally used in the political realm these days, that the other sense of it is perhaps falling by the wayside.

In D. H. Lawrence's short story "The Daughters of the Vicar, (1911)" Lawrence has one of his characters use the word "abortion" to describe a sickly and frail person. He describes this person in the prose as "a small, chetif man, scarcely larger than a boy of twelve." I believe that the common use of that time was to reference a disabled or severely underdeveloped person.