Not seen but heard in light fog? (6)
I believe the answer is:
missed
'not seen' is the definition.
The answer and definition can be both related to thinking as well as being past participle verbs.
Maybe there's a link between them I don't understand?
'heard in light fog?' is the wordplay.
'heard in' shows a homophone (sound like).
'light fog?' becomes 'mist' (I've seen this in another clue).
'mist' sounds like 'MISSED'.
'but' is the link.
Can you help me to learn more?
(Other definitions for missed that I've seen before include "failed to see" , "Suffered the lack of" , "came too late" , "Failed to hit target" , "Overlooked ?- ?? but not forgotten!" .)