Snatch young goat having a sleep (6)
I believe the answer is:
kidnap
'snatch' is the definition.
(synonyms)
'young goat having a sleep' is the wordplay.
'young goat' becomes 'kid' (I've seen this before).
'having' means one lot of letters go next to another.
'a sleep' becomes 'nap' (a nap is a short sleep).
'kid'+'nap'='KIDNAP'
(Other definitions for kidnap that I've seen before include "Seize and hold for ransom" , "'Abduct, snatch (6)'" , "Take person prisoner for ransom" , "deprive it of liberty" , "Abduct and hold for ransom" .)