The most common and most likely answer to this crossword clue is the 4 letter word DOUR
I've seen this crossword clue in The Times
D
O
U
R
More clues leading to the result DOUR
- Visit ancient city? It’s grim
- Forbidding party game to be taken up
- Unopened perfume’s grim
- Honesty can be disregarded; that’s grim
- Forbidding daughter to join quartet with no following
- Grim condo urgently blocked
- Grim smell with no discernible origin
- Grim half-hour following discharge
- Dismal party game is upsetting
- Driving on unpaved roads initially grim
Buddy explains!

The straight part
We know that "grim" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case grim = dour.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 DOUR mean?
DOUR adjective- Stern, harsh and forbidding.
- Unyielding and obstinate.
- Expressing gloom or melancholy; sullenly unhappy.