Failure as everyone gets upset in wood (8)
I believe the answer is:
collapse
'failure' is the definition.
(thesaurus)
'everyone gets upset in wood' is the wordplay.
'everyone' becomes 'all' (all people).
'gets upset' is a reversal indicator (I've seen 'getting upset' mean this).
'in' indicates putting letters inside.
'wood' becomes 'copse' (a copse is a small wood).
'all' reversed gives 'lla'.
'lla' put inside 'copse' is 'COLLAPSE'.
'as' acts as a link.
(Other definitions for collapse that I've seen before include "Suddenly fall down or give way" , "Crumble" , "Break-down or complete failure" , "Slump" , "Faint and fall" .)