Tea provided by sailor in mess (5)
I believe the answer is:
chaos
'mess' is the definition.
(thesaurus)
'tea provided by sailor' is the wordplay.
'tea' becomes 'cha' (cha is a type of tea).
'provided by' is a charade indicator (letters next to each other).
'sailor' becomes 'os' (ordinary seaman**).
'cha'+'os'='CHAOS'
'in' is the link.
(Other definitions for chaos that I've seen before include "Absence of order" , "upheaval" , "mess" , "A total shambles" , "State of extreme confusion and disorder" .)