Charlie, out of practice, may be surly (6)
I believe the answer is:
crusty
'surly' is the definition.
(thesaurus)
'charlie out of practice' is the wordplay.
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'out of practice' becomes 'rusty' ('rusty' can be a synonym of 'out of practice').
'c'+'rusty'='CRUSTY'
'may be' is the link.
(Other definitions for crusty that I've seen before include "Sour and brusque, like outer part of bread" , "bloomer like this?" , "Curtsy (anag.)" , "Well baked - short-tempered" , "Cross or harsh, like outer layer of loaf" .)