So-called "African unicorn" (5)
I believe the answer is:
okapi
'so-called african unicorn' 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 "Ruminant mammal of Africa" , "Wild African" , "Animal of central Africa" , "African animal like giraffe with shorter neck and striped body" , "One of the giraffe family" .)