Raved about bachelor unduly perhaps (6)
I believe the answer is:
adverb
'unduly perhaps' is the definition.
I can't judge whether this defines the answer.
'raved about bachelor' is the wordplay.
'about' indicates anagramming the letters.
'bachelor' becomes 'b' (abbreviation e.g. BA=Bachelor of Arts).
'raved' anagrammed gives 'adver'.
'adver'+'b'='ADVERB'
Can you help me to learn more?
(Other definitions for adverb that I've seen before include "Action word qualifier" , "-ly word" , "Perhaps stupidly" , "Word such as "quickly"" , "twelve for example" .)