n. 1 a sudden seizure of epilepsy, hysteria, apoplexy, fainting, or paralysis, with unconsciousness or convulsions. 2 a sudden brief attack of an illness or of symptoms (fit of coughing). 3 a sudden short bout or burst (fit of energy; fit of giggles). 4 colloq. an attack of strong feeling (fit of rage). 5 a capricious impulse; a mood (when the fit was on him). by (or in) fits and starts spasmodically. give a person a fit colloq. surprise or outrage him or her. have a fit colloq. be greatly surprised or outraged. in fits laughing uncontrollably.
[ ME, = position of danger, perh. = OE fitt conflict (?) ]