English to English

noun (n)

• a pause during which things are calm or activities are diminished(noun.time)

  Example:
  There was never a letup in the noise.
  

  Synonym:
  lull
  

  source: wordnet30
• Abatement; also, cessation; as, it blew a gale for three days without any let-up.(noun)

  source: webster1913