Paper recruits acceptable type (4)
I believe the answer is:
font
'type' is the definition.
(font is a kind of type)
'paper recruits acceptable' is the wordplay.
'paper' becomes 'ft'.
'recruits' is an insertion indicator.
'acceptable' becomes 'on' (I've seen this in other clues).
'ft' enclosing 'on' is 'FONT'.
(Other definitions for font that I've seen before include "Style of lettering" , "Baptismal bowl" , "Size and style of type" , "Vessel for baptismal water" , "Church feature" .)