1. Surpassing any previously established record
   "a record-breaking high jump"; "record-breaking crowds"

See also: best

• uncertified
• unchain
• unchained
• unchallengeable
• unchallenged
• unchangeability
• unchangeable
• unchangeableness
• unchangeably
• unchanged
• unchanging
• unchangingness
• unchaperoned
• uncharacteristic
• uncharacteristically
• uncharged
• uncharitable
• uncharitably
• uncharted
• unchartered
• unchaste
• unchastened
• uncheckable
• unchecked
• uncheerful