Likely imitative of non-verbal sounds used to indicate disagreement or discomfort. Compare nope, wherein the -p may represent closure often uttered at the end of the word no. Compare also um used to indicate hesitation. Attested from 1888.
Modern English dictionary
Explore and search massive catalog of over 900,000 word meanings.
Word of the Day
Get a curated memorable word every day.
Challenge yourself
Level up your vocabulary by setting personal goals.