Of limited extent, horse Grant trained (5-5)
I believe the answer is:
short-range
'of limited extent horse grant trained' is the definition.
I can't judge whether this defines the answer.
'horse grant trained' is the wordplay.
'trained' indicates an anagram (to train can mean to grow something into a shape).
'horse'+'grant'='horsegrant'
'horsegrant' with letters rearranged gives 'SHORT-RANGE'.
Can you help me to learn more?
(Other definitions for short-range that I've seen before include "Relating to a limited period or distance" , "Not stretching far into the future" .)