The most common and most likely answer to this crossword clue is the 10 letter word HAIRDRYERS
H
A
I
R
D
R
Y
E
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S
Buddy explains!
The straight part
We know that "they blow hot and cold" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they blow hot and cold = hairdryers.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 HAIRDRYERS mean?
HAIRDRYERS noun- A small electrical appliance for drying hair, by generating a stream of hot air.