After bad mood, ambassador creates part of a poem (7)
I believe the answer is:
strophe
'part of a poem' is the definition.
'strophe' can be an answer for 'part' (I have seen 'part of ode' mean 'strophe' so perhaps 'part' could also mean 'strophe'). I am not certain of the 'of a poem' bit.
'after bad mood ambassador' is the wordplay.
'after' is a charade indicator (letters next to each other).
'bad mood' becomes 'strop' (I've seen this before).
'ambassador' becomes 'he' (His or Her Excellency).
'strop' next to 'he' is 'STROPHE'.
'creates' is the link.
Can you help me to learn more?
(Other definitions for strophe that I've seen before include "stanza" , "Division of choral ode" , "Section of Greek choral ode; stop her (anagram)" , "Part of a lyric poem" , "Section of lyric poem" .)