Put forward (8)
'put forward' is the definition.
(I know that put forward can be written as nominate)
This is the entire clue.
(Other definitions for nominate that I've seen before include "Propose for office" , "Put forward (as candidate for election)" , "Specify (person for job)" , "Propose as a candidate" , "Propose - a mention (anag)" .)
(Other definitions for advanced that I've seen before include "Went ahead" , "The latest" , "Far on; complex" , "Progressed" , "Lent - brought forward" .)
(Other definitions for proposed that I've seen before include "Presented for consideration" , "Offered for consideration - perhaps marriage" , "Asked to marry" , "Nominated, put forward for consideration" , "Advocated" .)
'put forward' is the definition.
(to posit an idea is to put it forward)
This is all the clue.
(Other definitions for posit that I've seen before include "Lay down as principle" , "given proposition" , "Put forward (something) as a given" , "Put forward (a theory)" , "Put forward; place" .)