The most common and most likely answer to this crossword clue is the 5 letter word YOURS
I've seen this crossword clue in The Times
Y
O
U
R
S
Buddy explains!
The straight part
We know that "is for the solver to deal with?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case is for the solver to deal with? = yours.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 YOURS mean?
YOURS pronoun- That which belongs to you (singular); the possessive second-person singular pronoun used without a following noun.
- That which belongs to you (plural); the possessive second-person plural pronoun used without a following noun.
- Written at the end of a letter, before the signature.