Doctor embraces one with the trembling condition (6)
I believe the answer is:
dither
'trembling condition' is the definition.
(I've seen this before)
'doctor embraces one with the' is the wordplay.
'doctor' becomes 'dr' ('Dr' can be a synonym of 'doctor').
'embraces' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'with' is a charade indicator (letters next to each other).
'i'+'the'='ithe'
'dr' placed around 'ithe' is 'DITHER'.
(Other definitions for dither that I've seen before include "Be indecisive, hesitate" , "Hit red in order to vacillate" , "Shilly-shally" , "lather" , "Be in two minds" .)