Press pitch regularly ignored, which is funny (6)
I believe the answer is:
ironic
'is funny' is the definition.
(I've seen this before)
'press pitch regularly ignored' is the wordplay.
'press' becomes 'iron' (ironing is a kind of pressing).
'regularly ignored' means one should take alternating letters.
The alternating letters of 'pitch' are 'ic'.
'iron'+'ic'='IRONIC'
'which' is the link.
(Other definitions for ironic that I've seen before include "Paradoxical, contradictory" , "W. Country port, its Channel" , "Using the opposite of the truth for humorous effect" , "Describes a statement that says the opposite of what is clearly the case" , "Paradoxical or sarcastic" .)