Giraffe's relative (5)
I believe the answer is:
'giraffe's relative' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for okapi that I've seen before include "Giraffe-like animal with stripes" , "One of the giraffe family" , "beast from Africa" , "African animal related to the giraffe" , "rainforest ruminant" .)