He may be merry and wander drunkenly (6)
I believe the answer is:
andrew
'he may be merry' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'wander drunkenly' is the wordplay.
'drunkenly' is an anagram indicator.
'wander' anagrammed gives 'ANDREW'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for andrew that I've seen before include "apostle" , "November thirtieth is this saint's day" , "- Motion, Poet Laureate" , "Royal prince" , "- - Marr (TV)" .)