Now in trim, flaunt oneself (6)
I believe the answer is:
parade
'flaunt oneself' is the definition.
I can't tell whether this defines the answer.
'now in trim' is the wordplay.
'now' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'in' means one lot of letters goes inside another.
'trim' becomes 'pare' (synonyms).
'ad' placed into 'pare' is 'PARADE'.
Can you help me to learn more?
(Other definitions for parade that I've seen before include "Ostentation" , "Public walk or march" , "Easter ___ , 1948 film with Judy Garland and Fred Astaire" , "'Procession of bands, floats, etc (6)'" , "Flaunt; ceremonial march" .)