The most common and most likely answer to this crossword clue is the 4 letter word THAW
T
H
A
W
More clues leading to the result THAW
- What changed melting of ice caps, eg?
- What's changed in warmer weather?
- Getting warmer Thursday: not half warm, on reflection
- Defrost fruit after time
- Initially tense, hesitant and wary, become more relaxed
- What awful weather!
- Get warmer a week on Thursday
- What provoked increase in friendliness
- What could be an improvement in the weather
- What melts?
Buddy explains!

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 THAW mean?
THAW noun- The melting of ice, snow, or other congealed matter; the resolution of ice, or the like, into the state of a fluid; liquefaction by heat of anything congealed by frost
- A warmth of weather sufficient to melt that which is frozen
- To gradually melt, dissolve, or become fluid; to soften from frozen
- To become so warm as to melt ice and snow — said in reference to the weather, and used impersonally.
- To grow gentle or genial.
- To gradually cause frozen things (such as earth, snow, ice) to melt, soften, or dissolve.