Mums bed has charm (6)
I believe the answer is:
mascot
'charm' is the definition.
(synonyms)
'mums bed' is the wordplay.
'mums' becomes 'mas' ('ma' can be a synonym of 'mum').
'bed' becomes 'cot' (cot is a type of bed).
'mas'+'cot'='MASCOT'
'has' is the link.
(Other definitions for mascot that I've seen before include "that's charming?" , "Lucky person" , "Luck-bringer" , "Symbolic figure, of a team perhaps" , "Symbolic lucky figure" .)