Child having sleep in Shanghai? (6)
I believe the answer is:
kidnap
'shanghai?' is the definition.
(I know that shanghai is a more specific form of the action kidnap)
'child having sleep' is the wordplay.
'child' becomes 'kid' (synonyms).
'having' is a charade indicator (letters next to each other).
'sleep' becomes 'nap' (a nap is a short sleep).
'kid'+'nap'='KIDNAP'
'in' acts as a link.
(Other definitions for kidnap that I've seen before include "Seize and hold for ransom" , "'Abduct, snatch (6)'" , "Abduct (a person)" , "deprive it of liberty" , "Small island" .)