It is clear the French annoy (6)
I believe the answer is:
nettle
'annoy' is the definition.
('nettle' can be a synonym of 'annoy')
'it is clear the french' is the wordplay.
'it is clear' becomes 'nett' ('nett' can be similar in meaning to 'clear'**).
'the french' becomes 'le'.
'nett'+'le'='NETTLE'
(Other definitions for nettle that I've seen before include "Plant with stinging hairs" , "Sting or annoy with the plant" , "Upset" , "Growing" , "Stinging weed - pester" .)