decline in quality

Từ điển WordNet v3.1 - WordNet Dictionary

noun

process of changing to an inferior state
• Syn:
deterioration, declension, worsening
• Derivationally related forms:
worsen (for: worsening), decline (for: declension), deteriorate (for: deterioration)
• Hypernyms:
decline, diminution
• Hyponyms:
slump, slack, drop-off, falloff, falling off