The most common and most likely answer to this crossword clue is the 5 letter word HIPPO
I've seen this crossword clue in The Guardian
H
I
P
P
O
More clues leading to the result HIPPO
- Pelvis operation reversed for large mammal
- Fruit on Italian flower, one that's large and fleshy
- Big beast in foreign river
- What township police would need?
- Cool Italian banker’s thick-skinned customer
- Gregarious beast now in river?
- Thick-skinned type taking fruit by Italian river
- Native African transported by ship, possibly
- Beastly African in post office
- Statesmanship and politics together encapsulate this big beast
Buddy explains!

The straight part
We know that "Native African" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case native african = hippo.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does HIPPO mean?
HIPPO noun- A large, semi-aquatic, herbivorous (plant-eating) African mammal (Hippopotamus amphibius)