Weaker official about to admit abuse (7)

'weaker' is the definition.
('frail' can be similar in meaning to 'weak')

'official about to admit abuse' is the wordplay.
'official' becomes 'ref' (match official in football, say).
'about' says the letters should be written backwards.
'to admit' indicates putting letters inside.
'abuse' becomes 'rail' (railing is a kind of abusing).
'ref' backwards is 'fer'.
'fer' placed around 'rail' is 'FRAILER'.