One traditional athletics race keeping crowd riveted? (8)
I believe the answer is:
immobile
'riveted?' is the definition.
The answer and definition are not the same part of speech. However, adjectives and past participle verbs sometimes define each other.
'one traditional athletics race keeping crowd' is the wordplay.
'one' becomes 'i' (Roman numeral).
'traditional athletics race' becomes 'mile' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'keeping' is an insertion indicator (some letters kept inside).
'crowd' becomes 'mob' (mob can mean a crowd of people).
'mile' placed around 'mob' is 'mmobile'.
'i'+'mmobile'='IMMOBILE'
Can you help me to learn more?
(Other definitions for immobile that I've seen before include "Not going anywhere" , "fixed" , "stuck in the station, maybe" , "Can't travel" , "Not capable of movement" .)