Poking fun about attending a trial is terrible (9)

I believe the answer is:
satirical
'terrible' is the definition.
Both the answer and definition are adjectives. Maybe you can see an association between them that I can't see?
'poking fun about attending a trial' is the wordplay.
I cannot quite understand how this works, but
'about' could be 'ca' (abbreviation for 'circa') and 'ca' is found in the answer.
'attending' could be 'at' (e.g. at school means attending school) and 'at' is present in the answer.
This explanation may well be incorrect...
'is' acts as a link.
Can you help me to learn more?
(Other definitions for satirical that I've seen before include "Exposing human folly to ridicule" , "Mocking" , "Ironic - sarcastic" , "Describing irreverent humour" , "taunting?" .)
