Bee right over swallows (5)
I believe the answer is:
drone
'bee' is the definition.
(I know that drone is a type of bee)
'right over swallows' is the wordplay.
'right' becomes 'r' (common abbreviation).
'over' becomes 'done' (both can mean finished).
'swallows' indicates putting letters inside.
'r' inserted inside 'done' is 'DRONE'.
(Other definitions for drone that I've seen before include "boring speaker" , "Unmanned aerial vehicle" , "Monotonous low sound" , "Male honey bee, an idler" , "Buzzing sound" .)