doing it once is all right, but let it not turn into a habit; it's ok this time, but let's not make a habit of it

(dated) to threaten, to guarantee that there will be hell to pay, that there will be severe retribution, that there will be trouble

(informal) God forbid!

to be something to which one wouldn't say no, to be something that one wouldn't mind, to be most welcome

(games, idiomatic) that's not fair game

(slang) no glove, no love

(informal) not bad to look at, quite good-looking

to be no sucker, to not be easily taken in, to not let oneself be fooled easily

(transitive) not to let out of one's sight, not to take one's eyes off, to keep an eye on

(vulgar) to do fuck all, not to do a damn thing, to do nothing