Teaches ceramicists to become trivialists (13)
I believe the answer is:
trainspotters
'become trivialists' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'teaches ceramicists' is the wordplay.
'teaches' becomes 'trains' (training is a kind of teaching).
'ceramicists' becomes 'potters' ('potter' can be a synonym of 'ceramicist').
'trains'+'potters'='TRAINSPOTTERS'
'to' acts as a link.
Can you help me to learn more?
(Another definition for trainspotters that I've seen is " geeks".)