swell (n.) Look up swell at Dictionary.com
c. 1200, "a morbid swelling," from swell (v.). In reference to a rise of the sea, it is attested from c. 1600; of music, by 1803. The meaning "wealthy, elegant person" is first recorded 1786, connected to the now-obsolete sense "pompousness, arrogance" (1724), both from the notion of "puffed-up" demeanor or behavior.
swell (v.) Look up swell at Dictionary.com
Old English swellan "grow or make bigger" (past tense sweall, past participle swollen), from Proto-Germanic *swelnan (source also of Old Saxon swellan, Old Norse svella, Old Frisian swella, Middle Dutch swellen, Dutch zwellen, Old High German swellan, German schwellen), of unknown origin. Of emotions from late 14c., of music from 1749. Related: swelled; swollen; swelling.
swell (adj.) Look up swell at Dictionary.com
"fashionably dressed or equipped," 1810, from swell (n.) in the "stylish person" sense. As "good, excellent," by 1897; as a stand-alone expression of satisfaction it is recorded from 1930 in American English.