The most common and most likely answer to this crossword clue is the 6 letter word CUCKOO
I've seen this crossword clue in The Sunday Telegraph
C
U
C
K
O
O
Buddy explains!
The straight part
We know that "Wacky/winger" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case wacky/winger = cuckoo.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 CUCKOO mean?
CUCKOO noun- The two-note sound made by the cuckoo.
- A Barbadian food made from mashed okra and cornmeal.
- Any of various birds, of the family Cuculidae, famous for laying its eggs in the nests of other species; but especially the common cuckoo, Cuculus canorus, that has a characteristic two-note call.
- The sound of that particular bird.
- The bird-shaped figure found in cuckoo clocks.
- The cuckoo clock itself.
- A person who inveigles themselves into a place where they should not be (used especially in the phrase a cuckoo in the nest).
- Someone who is crazy.
- To make the call of a cuckoo.
- To repeat something incessantly.
- Crazy; not sane.