Mrs Dawson whipped fencer? (9)
I believe the answer is:
swordsman
'fencer?' is the definition.
('swordsman' can be a synonym of 'fencer')
'mrs dawson whipped' is the wordplay.
'whipped' indicates anagramming the letters.
'mrs'+'dawson'='mrsdawson'
'mrsdawson' anagrammed gives 'SWORDSMAN'.
(Other definitions for swordsman that I've seen before include "Person using old weapon - fencer" , "Male fencer" , "Fighter with a blade" , "Sandworms (anag.)" , "Skilled fencer" .)