Escape is hard, caught by toilet support (8)
I believe the answer is:
loophole
'escape' is the definition.
(thesaurus)
'hard caught by toilet support' is the wordplay.
'hard' becomes 'h'.
'caught by' is an insertion indicator.
'toilet' becomes 'loo' (loo is a kind of toilet).
'support' becomes 'pole' (poling is a kind of supporting**).
'loo'+'pole'='loopole'
'h' going within 'loopole' is 'LOOPHOLE'.
'is' acts as a link.
(Other definitions for loophole that I've seen before include "Weakness in law" , "Ambiguity in the law" , "Escape clause" , "way to escape penalty" , "Means of evasion" .)