Infectious
来自Big Physics
late Middle English: from late Latin infectio(n- ), from Latin inficere ‘dip in, taint’ (see infect).
etymonline
infectious (adj.)
"catching, having the quality of spreading from person to person, communicable by infection," 1540s of diseases, 1610s of emotions, actions, etc.; see infection + -ous. Earlier in the same sense were infectuous (late 15c.), infective (late 14c.). Related: Infectiously; infectiousness.
