The most common and most likely answer to this crossword clue is the 4 letter word REVS
I've seen this crossword clue in The Times
R
E
V
S
Buddy explains!
The straight part
We know that "measure of spin" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case measure of spin = revs.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 REVS mean?
REVS noun- Revolution
- A member of the Christian clergy; a minister.