balmy (adj.) Look up balmy at Dictionary.com
c. 1500, "delicately fragrant," from balm + -y (2). Figurative use for "soft and soothing" dates from c. 1600; of breezes, air, etc. "mild, fragrant" (combining both earlier senses) it is first attested 1704. Meaning "weak-minded, idiotic," 1851, is from London slang, perhaps by confusion with barmy. Related: Balmily.