Meaning

adjective actively or fully engaged or occupied

adjective overcrowded or cluttered with detail

adjective intrusive in a meddling or offensive manner

originEtymology tree English busy Proto-Indo-European *-yōs Proto-Indo-European *-tHós Proto-Indo-European *-istHos Proto-Germanic *-istaz Proto-West Germanic *-ist Old English -est Middle English -est English -est English busiest From busy + -est.

Etymology from Wiktionary, CC BY-SA 3.0