Lament getting temperamental around November (6)
I believe the answer is:
monody
'lament' is the definition.
(mournful song in ancient Greek drama)
'temperamental around november' is the wordplay.
'temperamental' becomes 'moody' (synonyms).
'around' means one lot of letters goes inside another.
'november' becomes 'N' (phonetic alphabet: alpha, bravo, charlie etc.).
'moody' placed around 'n' is 'MONODY'.
'getting' is the link.
(Other definitions for monody that I've seen before include "musical style" , "elegy" , "kind of poem" , "Song that's mournful" , "Plainchant, perhaps" .)