Idioms, Colloquialisms, and Slang
7.5.2 Idioms, Colloquialisms, and Slang
Some language is best avoided in material written for a professional or academic audience.
Idioms are fixed expressions that cannot be understood literally (kick the bucket, on a roll, put up with, pay attention). In addition, some may have multiple meanings that can be understood only in context (pass out, stand for). Idioms are not governed by any rules and each stands on its own. Be wary of using idioms, particularly for audiences that include readers whose first language is not English.
Colloquialisms (or casualisms2) are characteristic of informal, casual communication (ain't, anyways, cold turkey, flat line, OK, shell-shocked, tax hike).
Slang includes informal, nonstandard terms whose meanings are not readily understood by all speakers of a language. Sometimes slang words are newly coined (hick, rinky-dink, FAQ) and sometimes they are created by applying new meanings to existing words (bad, cool, awesome, random, killer).
Colloquialisms and slang should be avoided except in special situations, such as “flavorful” prose or direct quotations.
My sense is that part of the reason why Claude is able to survive is denial. He just says, flat out, “This ain't happening.”
The technical terminology specific to various disciplines is considered jargon and should be avoided (see 11.4, Correct and Preferred Usage, Jargon).