The old man with initially weak touch (3)
I believe the answer is:
paw
'touch' is the definition.
(paw can mean to touch or grope)
'the old man with initially weak' is the wordplay.
'the old man' becomes 'pa' (both can mean father).
'with' is a charade indicator (letters next to each other).
'initially' suggests taking the first letters.
The initial letter of 'weak' is 'w'.
'pa'+'w'='PAW'
(Other definitions for paw that I've seen before include "Animal foot or hill-billy dad" , "Foot of clawed animal" , "Hand; foot" , "Mammal's foot" , "Manhandle" .)