Please contribute for arch (5)
I believe the answer is:
ogive
'arch' is the definition.
(I know that ogive is a type of arch)
'please contribute' is the wordplay.
'please' becomes 'o' (form of address eg in an ode).
'contribute' becomes 'give' (synonyms).
'o'+'give'='OGIVE'
'for' is the link.
(Other definitions for ogive that I've seen before include "pointed window" , "Lancet arch" , "Feature of Gothic church" , "Pointed or Gothic arch" , "Mount --, Washington's home" .)