Posh boy Henry grabbed - I owned up (3-2-3)
I believe the answer is:
lah-di-dah
'posh' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
(Other definitions for lah-di-dah that I've seen before include "with a superior attitude?" , "Pretentiously refined, affected in speech and manners" , "Affectedly posh" , "Affectedly genteel, highfalutin" , "Pretentious, snobbish (colloq.)" .)