1. Bent in different directions; wreathed; twisted; winding; as, a tortuous train; a tortuous train; a tortuous leaf or corolla. The badger made his dark and tortuous hole on the side of every hill where the copsewood grew thick. (Macaulay)
2. Deviating from rectitude; indirect; erroneous; deceitful. That course became somewhat lesstortuous, when the battle of the Boyne had cowed the spirit of the Jakobites. (Macaulay)
3. Injurious: tortious.
4. (Science: astronomy) oblique; applied to the six signs of the zodiac (from Capricorn to gemini) which ascend most rapidly and obliquely. Infortunate ascendent tortuous. (Chaucer) Tortuously, Tortuousness.
Origin: OE. Tortuos, L.tortuosus, fr.tortus a twisting, winding, fr. Torquere, tortum, to twist: cf. F. Tortueux. See Torture.