Lie in bed, shaky, not fit to eat (8)
I believe the answer is:
inedible
'not fit to eat' is the definition.
(I've seen this before)
'lie in bed shaky' is the wordplay.
'shaky' is an anagram indicator.
'lie'+'in'+'bed'='lieinbed'
'lieinbed' anagrammed gives 'INEDIBLE'.
(Other definitions for inedible that I've seen before include "Awful to taste" , "Not good as food" , "not to be swallowed" , "Uneatable" , "Not suitable for consumption" .)