with all one's might / non-stop, left and right, like crazy, aplenty

(figuratively) to sit back and do nothing

(figuratively) to sit back and do nothing, to cross one's arms and wait, to stand by idly

(informal, figuratively) I'm flabbergasted, I'm speechless

(informal, figuratively) to act tough

in one's shirt sleeves, in shirt sleeves, casually dressed

(simile) long as one's arm (very long, endless)

(simile) very big (of a lie, a flattery, etc.)

at arm's length, with one's arm stretched / single-handedly and with great difficulty, by exerting a lot of effort

(transitive, figuratively) to have something on one's hands