The most common and most likely answer to this crossword clue is the 5 letter word GOLEM
I've seen this crossword clue in The Daily Telegraph
G
O
L
E
M
Buddy explains!
The straight part
We know that "dolt" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dolt = golem.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 GOLEM mean?
GOLEM noun- A humanoid creature made from clay, animated by magic.
- (by extension) A humanoid creature made from any previously inanimate matter, such as wood or stone, animated by magic.