glad (adj.) Look up glad at Dictionary.com
Old English glæd "bright, shining, joyous," from Proto-Germanic *glada- (cognates: Old Norse glaðr "smooth, bright, glad," Danish glad "glad, joyful," Old Saxon gladmod "glad," Old Frisian gled "smooth," Dutch glad "slippery," German glatt "smooth"), from PIE *ghel- (2) "to shine," with derivatives referring to bright materials and gold (see glass). The modern sense is much weakened. Slang glad rags "one's best clothes" first recorded 1902.