All right for a detective to get animal (5)
I believe the answer is:
okapi
'animal' is the definition.
(African mammal)
'all right for a detective' is the wordplay.
'all right' becomes 'ok' (synonyms).
'for' means one lot of letters go next to another.
'detective' becomes 'PI' (short for private investigator).
'ok'+'a'+'pi'='OKAPI'
'to get' acts as a link.
(Other definitions for okapi that I've seen before include "Wild African" , "Small giraffe" , "Shy Zairean ruminant" , "Wild animal" , "Rare mammal" .)