The most common and most likely answer to this crossword clue is the 9 letter word BLACKHEAD
I've seen this crossword clue in The Guardian
B
L
A
C
K
H
E
A
D
More clues leading to the result BLACKHEAD
Buddy explains!
The straight part
We know that "Spot" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case spot = blackhead.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 BLACKHEAD mean?
BLACKHEAD noun- A comedo, a skin blemish, a type of acne vulgaris, where a pore becomes clogged with a dark, hard, cheesy keratin-filled substance forming a hard black "head" on the skin's surface.
- A form of histomoniasis in poultry, characterized by cyanotic discoloration on the bird's head.
- A scaup: any of various ducks of the genus Aythya.