The most common and most likely answer to this crossword clue is the 3 letter word ANY
I've seen this crossword clue in Independent
A
N
Y
More clues leading to the result ANY
- A new daily, ultimately not one in particular
- A state in America, none in particular
- A US city, no matter which
- Clown losing hat: which you like?
- Some always gathered about noon
- A state in America – no matter which?
- Answer back from teen and from tweeny. ‘Whatever‘
- One in Newcastle, we hear
- A lot? Not a lot — some, or one!
- No matter which area, state half of its capital
Buddy explains!

The straight part
We know that "Whatever" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case whatever = any.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 ANY mean?
ANY adverb- To even the slightest extent, at all.
- Any thing(s) or person(s).