Shakespeare uses the verb in this sense, but by his time it had already developed other senses that have been lost now: “fear, be afraid” and “suspect, have suspicions about”. When Prince Hal says to Poins, about taking on Falstaff and the others in a fight, “I doubt they will be too hard for us” (Henry IV part 1 I.ii.179), he is saying they might lose, not win; when the Messenger approaches Macduff’s wife to say “I doubt some danger does approach you nearly” (Macbeth IV.ii.67), he is advising her to flee not stay; and when Pandarus says to Cressida, about Troilus, “I doubt he be hurt” (Troilus and Cressida I.ii.276), he thinks he is hurt, not that he isn’t. The “suspicion” sense is most famously preserved in Hamlet’s soliloquy, “I doubt some foul play” (Hamlet I.ii.256), soon after reinforced by similar uses from both Gertrude (II.ii.56) and Polonius, reading Hamlet’s letter to Ophelia, “Doubt truth to be a liar” (II.ii.117).

David Crystal is the author, with Ben Crystal, of Shakespeare’s Words (Penguin)