Old-fashioned foxtrot — out of practice, missing lead (5)
I believe the answer is:
fusty
'old-fashioned' is the definition.
(thesaurus)
'foxtrot out of practice missing lead' is the wordplay.
'foxtrot' becomes 'f' (phonetic alphabet: alpha, bravo, charlie etc.).
'out of practice' becomes 'rusty' ('rusty' can be a synonym of 'out of practice').
'missing lead' means to remove the first letter (the letter which leads the word is removed).
'rusty' with its first letter taken away is 'usty'.
'f'+'usty'='FUSTY'
(Other definitions for fusty that I've seen before include "Stale-smelling" , "Smelling stale or damp" .)