Knave, visual and humorous (7)
I believe the answer is:
jocular
'humorous' is the definition.
('jocular' can be similar in meaning to 'humorous')
'knave visual' is the wordplay.
'knave' becomes 'j'.
'visual' becomes 'ocular' ('ocular' can be a synonym of 'visual').
'j'+'ocular'='JOCULAR'
'and' is the link.
(Other definitions for jocular that I've seen before include "funny" , "With jokes and good humour" , "Humorous or playful" , "Humorous, joking" , "Given to telling gags (and having fun)" .)