Insolent men got oddly drowsy (9)

I believe the answer is:

somnolent

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'drowsy' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for somnolent that I've seen before include "falling asleep" , "drifting off" , "Comatose" , "Lent moons (anag.)" , "Sleepy, drowsy" .)

I've seen this clue in The Daily Express.

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