The most common and most likely answer to this crossword clue is the 5 letter word RHEUM
I've seen this crossword clue in The Daily Telegraph
R
H
E
U
M
More clues leading to the result RHEUM
- Discharge right hand man originally supporting group of nations
- It may indicate a cold part of house, I hear
- Discharge gas into drink
- Watery stuff he found in drink
- Discharge fellow into alcoholic drink
- Cold drink pumped with gas
- Discharge of gas put through drink
- Hot Englishman’s head, smothered in strange watery discharge
- Space, they say, is cold
- Watery fluid in said space
Buddy explains!
The straight part
We know that "Sign of a cold" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sign of a cold = rheum.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 RHEUM mean?
RHEUM noun- Watery or thin discharge of serum or mucus, especially from the eyes or nose, formerly thought to cause disease.
- Illness or disease thought to be caused by such secretions; a catarrh, a cold; rheumatism.
- Tears.