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Definitions

once in a blue moon

[wuhns in uh bloo moon] / ˈwʌns ɪn ə ˈblu ˈmun /
ADVERB
hardly
Synonyms
STRONGEST
barely comparatively practically rarely seldom simply somewhat
STRONG
just
WEAK
almost inconceivably almost not by a hair by no means detectably faintly gradually imperceptibly infrequently little no more than no way not a bit not at all not by much not likely not markedly not measurably not much not notably not noticeably not often not quite only only just perceptibly pretty near scantly slightly sparsely sporadically with trouble
Antonyms
STRONGEST
frequently
WEAK
very
ADVERB
now and then
Synonyms
STRONGEST
every now and then every so often infrequently intermittently now and again occasionally periodically sporadically
WEAK
at intervals at times every once in a while from time to time hardly irregularly not often off and on on occasion once and again once in a while once or twice sometimes
ADVERB
occasionally
Synonyms
STRONGEST
hardly infrequently periodically seldom sometimes sporadically
WEAK
at intervals at random at times every so often from time to time irregularly now and again on occasion once in a while once or twice uncommonly
Antonyms
WEAK
always constantly frequently regularly steadily usually
ADVERB
on and off
Synonyms
WEAK
at intervals at times discontinuously every now and then every once in a while every so often from time to time hardly infrequently intermittently irregularly now and again now and then occasionally off and on on occasion once in a while periodically sometimes sporadically
ADVERB
once in a while
Synonyms
WEAK
at intervals at times every now and then every so often from time to time hardly infrequently irregularly now and again on occasion periodically rarely seldom sometimes sporadically
ADVERB
seldom
Synonyms
STRONGEST
a few times hardly occasionally rarely scarcely sometimes sporadically
WEAK
every now and then from time to time hardly ever in a few cases inhabitually irregularly little not often not very often on and off once in a while scarcely ever semioccasionally uncommonly unoften unusually whimsically
Antonyms
STRONGEST
frequently regularly
WEAK
often usually
ADVERB
sometimes
Synonyms
STRONGEST
consistently constantly frequently occasionally
WEAK
at intervals at times ever and again every so often from time to time here and there intermittently now and again now and then off and on on occasion once in a while periodically recurrently
Antonyms
WEAK
never
ADVERB
sporadically
Synonyms
STRONGEST
intermittently now and then occasionally rarely seldom sparingly
WEAK
hardly hardly ever little not regularly scarcely uncommonly unusually
Antonyms
STRONGEST
frequently regularly usually

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

It's a phenomenon - or, to use Chappell's terminology, a Femininomenon - that only occurs once in a blue moon.

From BBC • Sep. 13, 2024

“I drive that car maybe once in a blue moon and I loved that car.”

From Washington Times • May 22, 2023

So their metabolism must allow them to store energy to persist long periods without food, then release energy to swim against strong currents once in a blue moon.

From Scientific American • Feb. 24, 2023

While this isn't a huge problem when done once in a blue moon, storing wet or dirty shears and knives over time will start taking its toll…mostly in the name of rust.

From Salon • May 8, 2022

Oh, I get it—it’s rare, like once in a blue moon.

From "Booked" by Kwame Alexander