The most common and most likely answer to this crossword clue is the 4 letter word CRUX
I've seen this crossword clue in The Guardian
C
R
U
X
More clues leading to the result CRUX
- Puzzle presented by roof supports, we hear
- Nonconformist church raised cross — what’s the point?
- Leaders of cardiological radiology unit x-rayed heart
- Essential point of a tenth vineyard?
- Key to problem in sound pairs of bent roof timbers
- Core Conservative vote keeping united to support Right
- Key point of vote on vineyard
- A key item in vintage times
- A crossword!
- Essentially scrub before opening X-ray centre
Buddy explains!
The straight part
We know that "heart" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case heart = crux.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 CRUX mean?
CRUX noun- The basic, central, or essential point or feature.
- The critical or transitional moment or issue, a turning point.
- A puzzle or difficulty.
- The hardest point of a climb.
- A cross on a coat of arms.