Mounts donkey, keeping colt to last (7)
I believe the answer is:
ascends
'mounts' is the definition.
(I've seen this before)
'donkey keeping colt to last' is the wordplay.
'donkey' becomes 'ass' (ass is a term for a donkey).
'keeping' indicates putting letters inside.
'colt' becomes 'c' (this might be a standard abbreviation I've not previously seen).
'to last' becomes 'end' (I've seen this in another clue).
'c'+'end'='cend'
'ass' going around 'cend' is 'ASCENDS'.
Can you help me to learn more?
(Other definitions for ascends that I've seen before include "Moves upwards" , "Rises" , "Travels upwards" , "Climbs, mounts" .)