Snatch some sleep after Josh (6)
I believe the answer is:
kidnap
'snatch' is the definition.
(I know that snatch can be written as kidnap)
'some sleep after josh' is the wordplay.
'some sleep' becomes 'nap' (a nap is a short sleep).
'after' is a charade indicator (letters next to each other).
'josh' becomes 'kid' (I've seen this before).
'nap' after 'kid' is 'KIDNAP'.
(Other definitions for kidnap that I've seen before include "Take person prisoner for ransom" , "Seize, usually for ransom" , "Seize and hold for ransom" , "deprive it of liberty" , "Abduct and hold for ransom" .)