Bill's father maintaining position (5)
I believe the answer is:
flier
'bill's' is the definition.
(synonyms)
'father maintaining position' is the wordplay.
'father' becomes 'fr' (abbreviation as in a priest's title).
'maintaining' indicates putting letters inside (inserted letters are held or maintained).
'position' becomes 'lie' (lie can mean to place or position).
'fr' enclosing 'lie' is 'FLIER'.
(Other definitions for flier that I've seen before include "Turkey perhaps?" , "Advertisement" , "PO, for example" , "Good start" , "Leaflet for distribution" .)