The most common and most likely answer to this crossword clue is the 7 letter word WHOPPER
W
H
O
P
P
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R
More clues leading to the result WHOPPER
- Women's jumper is unusually large one
- Say Saddam has chemical and biological weapons in 1910
- Giant beginning to whimper over flea, perhaps?
- Wife has jumper, something very large
- Fairy story with frog, perhaps?
- Lie with 9 or 5?
- Women anticipating skipper’s lie
- Monster fiction?
- First glimpse of white rabbit, say? A big one
- Wide container for something very big
Buddy explains!

The straight part
We know that "A big one" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a big one = whopper.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 WHOPPER mean?
WHOPPER noun- Something remarkably large.
- An outrageous or blatant lie.