The most common and most likely answer to this crossword clue is the 5 letter word DROOP
I've seen this crossword clue in Financial Times
D
R
O
O
P
More clues leading to the result DROOP
- Democrat with inadequate backing in decline
- Feeble Democrat raised flag
- Flag lowered finally, miserable in retreat
- Become dejected when inferior diamonds returned
- Band ultimately mean to raise flag
- Decline operation under doctor who’s finishing
- Look defeated – day turning not so good
- Decline a small drink, imbibing nothing
- Shed containing old sink
- Doctor round surgery to wilt from tiredness
Buddy explains!

The straight part
We know that "decline" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case decline = droop.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 DROOP mean?
DROOP noun- Something which is limp or sagging
- A condition or posture of drooping
- To hang downward; to sag.
- To slowly become limp; to bend gradually.
- To lose all energy, enthusiasm or happiness; to flag.
- To allow to droop or sink.
- To proceed downward, or toward a close; to decline.