Drunk latched on for contest (9)
I believe the answer is:
decathlon
'contest' is the definition.
(decathlon is a kind of contest)
'drunk latched on' is the wordplay.
'drunk' is an anagram indicator.
'latched' is an anagram of 'decathl'.
'decathl'+'on'='DECATHLON'
'for' is the link.
(Other definitions for decathlon that I've seen before include "Athletics contest" , "Versatile Olympic event" , "Athletic event" , "sporting contest" , "Latched on to athletic competition of 10 events" .)