The most common and most likely answer to this crossword clue is the 5 letter word DWARF
I've seen this crossword clue in The Daily Telegraph
D
W
A
R
F
More clues leading to the result DWARF
- Happy for one to turn off raw data, but not entirely
- Small person’s notes about conflict
- Doc perhaps died following cold’s recurrence
- Sleepy, maybe, getting stuck into Cold War fiction
- Doc possibly moves forward, or quits
- Happy, say, moving forward
- Overshadow Snow White’s friend
- Happy, perhaps, participating in cold war film
- Daughter initially feared rabbit asking “What’s up, Doc?”
- King getting wings clipped over female, very petite
Buddy explains!

The straight part
We know that "Overshadow/friend of Snow White" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case overshadow/friend of snow white = dwarf.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 DWARF mean?
DWARF noun- Any member of a race of beings from (especially Scandinavian and other Germanic) folklore, usually depicted as having some sort of supernatural powers and being skilled in crafting and metalworking, often as short with long beards, and sometimes as clashing with elves.
- A person of short stature, often one whose limbs are disproportionately small in relation to the body as compared with normal adults, usually as the result of a genetic condition.
- An animal, plant or other thing much smaller than the usual of its sort.
- A star of relatively small size.
- To render (much) smaller, turn into a dwarf (version).
- To make appear (much) smaller, puny, tiny.
- To make appear insignificant.
- To become (much) smaller.
- To hinder from growing to the natural size; to make or keep small; to stunt.
- Miniature.