Pitiful father gets the twitch (8)
I believe the answer is:
pathetic
'pitiful' is the definition.
(I know that pitiful can be written as pathetic)
'father gets the twitch' is the wordplay.
'father' becomes 'pa' (pa can mean dad or father).
'gets' says to put letters next to each other.
'twitch' becomes 'tic' (tic is a kind of twitch).
'pa'+'the'+'tic'='PATHETIC'
(Other definitions for pathetic that I've seen before include "Poignant or hopelessly inadequate" , "arousing contempt" , "Tip cheat - truly sad" , "really pitiful" , "Hapless, miserable" .)