Complain as former job's former uniform taken in (11)
I believe the answer is:
expostulate
'complain' is the definition.
(thesaurus)
'former job's former uniform taken in' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'job' becomes 'post' (post is a kind of job).
'former' becomes 'late' (late can mean former or previous).
'uniform' becomes 'U' (phonetic alphabet: alpha, bravo, charlie etc.).
'taken in' is an insertion indicator.
'post'+'late'='postlate'
'postlate' enclosing 'u' is 'postulate'.
'ex'+'postulate'='EXPOSTULATE'
'as' acts as a link.
(Other definitions for expostulate that I've seen before include "remonstrance" , "Argue protestingly" , "Express strong disagreement" , "find fault with" , "Reason" .)