Showing false modesty, leading around rodent (5)
I believe the answer is:
coypu
'rodent' is the definition.
(I know that coypu is a type of rodent)
'showing false modesty leading around' is the wordplay.
'showing false modesty' becomes 'coy' (coy means falsely modest or shy).
'leading' becomes 'up' (similar in meaning).
'around' says the letters should be written backwards.
'up' reversed gives 'pu'.
'coy'+'pu'='COYPU'
(Other definitions for coypu that I've seen before include "Aquatic beaver-like rodent" , "Creature in fur coat" , "Large South American aquatic rodent" , "rodents" , "S. American "beaver"" .)