n. & v.
n. 1 a feeling of uncertainty; an undecided state of mind (be in no doubt about; have no doubt that). 2 (often foll. by of, about) an inclination to disbelieve (have one's doubts about). 3 an uncertain state of things. 4 a lack of full proof or clear indication (benefit of the doubt).
v. 1 tr. (often foll. by whether, if, that + clause; also foll. (after neg. or interrog.) by but, but that) feel uncertain or undecided about (I doubt that you are right; I do not doubt but that you are wrong). 2 tr. hesitate to believe or trust. 3 intr. (often foll. by of) feel uncertain or undecided; have doubts (never doubted of success). 4 tr. call in question. 5 tr. Brit. archaic or dial. rather think that; suspect or fear that (I doubt we are late). beyond doubt certainly. doubting Thomas an incredulous or sceptical person (after John 20:24-29). in doubt uncertain; open to question. no doubt certainly; probably; admittedly. without doubt (or a doubt) certainly. doubtable adj. doubter n. doubtingly adv.
[ ME doute f. OF doute (n.), douter (v.) f. L dubitare hesitate; mod. spelling after L ]