He's plumb suspended! (3)
I believe the answer is:
bob
'he's' is the definition.
(short for Robert)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for bob that I've seen before include "Change" , "Move up and down as in water" , "Hairstyle cut shortly and evenly all round" , "way locks can be arranged" , "Short cut" .)