Begin destroying main tent for fun (13)
I believe the answer is:
entertainment
'fun' is the definition.
(thesaurus)
'begin destroying main tent' is the wordplay.
'begin' becomes 'enter'.
'destroying' is an anagram indicator.
'main'+'tent'='maintent'
'maintent' is an anagram of 'tainment'.
'enter'+'tainment'='ENTERTAINMENT'
'for' is the link.
(Other definitions for entertainment that I've seen before include "show business" , "sport" , "Provision of hospitality" , "fun" , "Public show; hospitality" .)