Extremely pitiful stranger is drudge (7)
I believe the answer is:
plodder
'drudge' is the definition.
(plodder is a kind of drudge)
'extremely pitiful stranger' is the wordplay.
'extremely' means to remove the middle letters.
'stranger' becomes 'odder' (I've seen this before).
'pitiful' with its centre taken out is 'pl'.
'pl'+'odder'='PLODDER'
'is' acts as a link.
(Other definitions for plodder that I've seen before include "One who walks laboriously or works slowly" , "Slow dull worker" .)