Bridge partner devours cake less the icing - most unhealthy (7)
I believe the answer is:
weakest
'most unhealthy' is the definition.
Both the answer and definition are superlative adjectives. Perhaps you can see a link between them that I don't see?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for weakest that I've seen before include "Least powerful" , "Least strong" , "like some television links?" , "Having minimum power" .)