There cabman shakes in waiting room (11)
I believe the answer is:
antechamber
'waiting room' is the definition.
(I've seen this before)
'there cabman shakes' is the wordplay.
'shakes' indicates an anagram.
'there'+'cabman'='therecabman'
'therecabman' anagrammed gives 'ANTECHAMBER'.
'in' is the link.
(Other definitions for antechamber that I've seen before include "Small room leading to a main one" , "External room" , "Small room before a larger one" , "room outside another" , "Small entrance room" .)