1. An agent that induces drowsiness or sleep

Type of: agent

• uprightness
• uprise
• uprising
• upriver
• uproar
• uproarious
• uproariously
• uproot
• uprooter
• uprush
• ups and downs
• ups-a-daisy
• Upsala
• upscale
• upset
• upset price
• upset stomach
• upsetter
• upsetting
• upshot
• upside
• upside-down
• upside-down cake
• upsilon
• upskill