The most common and most likely answer to this crossword clue is the 4 letter word MOOT
I've seen this crossword clue in The Guardian
M
O
O
T
More clues leading to the result MOOT
- Debatable witticism about love
- What cows go through, initially open
- Low tide initially doubtful
- Dispute low temperature
- Low temperature is subject to debate
- Cruise perhaps tipped to win Oscar? Doubtful
- Low temperature is debatable
- Lacking determination as yet, in low temperature
- … put forward as low point, ultimately
- Dispute using low tactics initially
Buddy explains!

The straight part
We know that "doubtful" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case doubtful = moot.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 MOOT mean?
MOOT noun- A moot court.
- A system of arbitration in many areas of Africa in which the primary goal is to settle a dispute and reintegrate adversaries into society rather than assess penalties.
- A gathering of Rovers, usually in the form of a camp lasting 2 weeks.
- A social gathering of pagans, normally held in a public house.
- An assembly (usually for decision-making in a locality).
- A ring for gauging wooden pins.
- Subject to discussion (originally at a moot); arguable, debatable, unsolved or impossible to solve.
- Being an exercise of thought; academic.
- Having no practical impact or relevance.
- A whisper, or an insinuation, also gossip or rumors.
- (rural) Talk.
- To bring up as a subject for debate, to propose.
- To discuss or debate.
- To make or declare irrelevant.
- To argue or plead in a supposed case.
- To talk or speak.
- To say, utter, also insinuate.
- Vagina.
- The stump of a tree; the roots and bottom end of a felled tree.
- To take root and begin to grow.
- To turn up soil or dig up roots, especially an animal with the snout.