Run in second of marathons? Trot maybe around the others? (8)
I believe the answer is:
arrested
'run in' is the definition.
(I've seen this in another clue)
'second of marathons? trot maybe around the others?' is the wordplay.
'second of marathons?' becomes 'a' (end letter of 'marathons').
'trot maybe' becomes 'red' (Trotskyite - red can informally mean communist. I am not sure about the 'maybe' bit.).
'around' is an insertion indicator.
'the others?' becomes 'rest' (eg the rest of a group).
'red' going around 'rest' is 'rrested'.
'a'+'rrested'='ARRESTED'
Can you help me to learn more?
(Other definitions for arrested that I've seen before include "Stopped - took into custody" , "Taken into custody, being serrated" , "Stopped or slowed down development" , "stalled" , "Detained by legal authority" .)