The most common and most likely answer to this crossword clue is the 5 plus 8 letter word PRIME MINISTER
I've seen this crossword clue in The Guardian
P
R
I
M
E
M
I
N
I
S
T
E
R
More clues leading to the result PRIME MINISTER
- Government leader to prepare member of the clergy
- Serve under first-rate cabinet-maker?
- Coach clergyman to become senior politician
- Prepare clergyman for the highest office?
- Brief address of surgeon sent round in May
- Quiet merriment is organised around 1 May?
- Politician offering terms ripe for negotiation, including car
- What Johnson is May to July?
- Prepare care for leader
- May. for example, prepare to fire member of clergy
Buddy explains!

The straight part
We know that "May?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case may? = prime minister.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.