The most common and most likely answer to this crossword clue is the 7 letter word SPECKLE
I've seen this crossword clue in The Guardian
S
P
E
C
K
L
E
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 = speckle.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 SPECKLE mean?
SPECKLE noun- A small spot or speck on the skin, plumage or foliage.
- The random distribution of light when it is scattered by a rough surface.
- Kind; sort.
- A cluster of interchromatin granules in a nucleus
- To mark with speckles.