Section includes a decoy (4)
I believe the answer is:
bait
'decoy' is the definition.
('bait' can be a synonym of 'decoy')
'section includes a' is the wordplay.
'section' becomes 'bit' (I've seen this in other clues).
'includes' indicates putting letters inside.
'bit' going around 'a' is 'BAIT'.
(Other definitions for bait that I've seen before include "Fishing lure" , "Enticement for fish" , "Lure; tease" , "Tempt" , "N in radio comms" .)