Amusing wordplay is hard to beat (6)
I believe the answer is:
punish
'beat' is the definition.
(I've seen this before)
'amusing wordplay is hard' is the wordplay.
'amusing wordplay' becomes 'pun' (synonyms. I am not sure about the 'amusing' bit.).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'pun'+'is'+'h'='PUNISH'
'to' is the link.
Can you help me to learn more?
(Other definitions for punish that I've seen before include "Fine maybe" , "Treat harshly or severely" , "Flog" , "Like wordplay in speech" , "Penalise" .)