Beam is taken in by hint (5)
I believe the answer is:
joist
'beam' is the definition.
(joist is a kind of beam)
'is taken in by hint' is the wordplay.
'taken in by' means one lot of letters goes inside another.
'hint' becomes 'jot' ('jot' can be a synonym of 'hint').
'is' inserted within 'jot' is 'JOIST'.
(Other definitions for joist that I've seen before include "Timber or steel roof or floor support" , "Beam supporting floors and roofs" .)