Five years of lechery and alcohol (7)
I believe the answer is:
lustrum
'five years' is the definition.
(I've seen this before)
'lechery and alcohol' is the wordplay.
'lechery' becomes 'lust' (I've seen this in other clues).
'and' is a charade indicator (letters next to each other).
'alcohol' becomes 'rum' (alcoholic spirit).
'lust'+'rum'='LUSTRUM'
'of' acts as a link.
(Other definitions for lustrum that I've seen before include "Period of five years" , "several years" , "Period of 20 ac years" , "Five-year period" .)