Thesaurus.com
Dictionary.com
Definitions

deadening

[ded-n-ing] / ˈdɛd n ɪŋ /
ADJECTIVE
narcotic
Synonyms
STRONGEST
calming
STRONG
analgesic anesthetic hypnotic opiate sedative soporific
WEAK
numbing somnifacient somnific somnolent somnorific soporiferous stupefacient stupefactive stupefying
Antonyms
STRONG
exciting stimulating
ADJECTIVE
soporific
Synonyms
STRONG
anesthetic calming hypnotic narcotic opiate sedative
WEAK
balmy dozy drowsy dull mesmerizing nodding numbing quietening slumberous snoozy somniferous somnolent soothing tranquilizing
Antonyms
STRONG
upsetting
WEAK
awake conscious exciting invigorating stimulating
NOUN
somnifacient
Synonyms
WEAK
anesthetic balmy calming dozy drowsy dull hypnotic mesmerizing narcotic nodding numbing opiate quietening sedative slumberous snoozy somniferous somnolent soothing tranquilizing

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.