n.any agent that produces relaxation

"music is a good relaxer"

Relaxer
Multimineral no-mix relaxer
CONDITIONING HAIR RELAXER SYSTEM
Hair relaxer composition and associated methods
Relaxer-Based Single Crystal Materials for Ultrasonic Transducer Applications
Hair Relaxer Use and Risk of Uterine Leiomyomata in African-American Women
Ingestion of Caustic Hair Relaxer: Is Endoscopy Necessary?
Oral and airway sequelae after hair relaxer ingestion.
Chloretone as a trematode relaxer, and its use in mass-collecting techniques.
Compositional instability and the resultant charge variations in mixed B‐site cation relaxer ferroelectrics