The most common and most likely answer to this crossword clue is the 4 letter word DUCK
I've seen this crossword clue in Independent
D
U
C
K
More clues leading to the result DUCK
Buddy explains!

The straight part
We know that "Steer clear of/Donald!" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case steer clear of/donald! = duck.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 DUCK mean?
DUCK verb- To quickly lower the head or body in order to prevent it from being struck by something.
- To quickly lower (the head) in order to prevent it from being struck by something.
- To lower (something) into water; to thrust or plunge under liquid and suddenly withdraw.
- To go under the surface of water and immediately reappear; to plunge one's head into water or other liquid.
- To bow.
- To evade doing something.
- To lower the volume of (a sound) so that other sounds in the mix can be heard more clearly.
- To enter a place for a short moment.
- An aquatic bird of the family Anatidae, having a flat bill and webbed feet.
- Specifically, an adult female duck; contrasted with drake and with duckling.
- The flesh of a duck used as food.
- A batsman's score of zero after getting out. (short for duck's egg, since the digit "0" is round like an egg.)
- A playing card with the rank of two.
- A partly-flooded cave passage with limited air space.
- A building intentionally constructed in the shape of an everyday object to which it is related.
- A marble to be shot at with another marble (the shooter) in children's games.
- A cairn used to mark a trail.
- One of the weights used to hold a spline in place for the purpose of drawing a curve.
- A long-necked medical urinal for men.
- A person or thing that is helpless, inefficient or disabled.
- An elected official who has lost the recent election or is not eligible for reelection and is marking time until leaving office.
- A person who cannot fulfill their contracts.
- A tightly-woven cotton fabric used as sailcloth.
- (in plural) Trousers made of such material.
- A term of endearment; pet; darling.
- Dear, mate (informal way of addressing a friend or stranger).