Deviate, v. i. [imp. & p. p. Deviated; p. pr. & vb. n. Deviating.]
Etymology: [L. deviare to deviate; de + viare to go, travel, via way. See Viaduct.]
To go out of the way; to turn aside from a course or a method; to stray or go astray; to err; to digress; to diverge; to vary. Thus Pegasus, a nearer way to take, May boldly deviate from the common track. Pope.
Syn. -- To swerve; stray; wander; digress; depart; deflect; err.
1 other Webster entry under this spelling
Deviate, v. t.
To cause to deviate. [R.] To deviate a needle. J. D. Forbes.
Shades of meaning
Fernald has no entry of its own for deviate; he lists it under bend, wander.
Where he writes about it:
Deflect, deviate, and diverge are said of any turning away; deviate commonly of a slight and gradual movement, diverge of a more sharp and decided one. — from bend
To wander (AS. windan, wind) is to move in an indefinite or indeterminate way which may or may not be a departure from a prescribed way; to deviate (L. de, from, and via, a way) is to turn from a prescribed or right way, physically, mentally, or morally, usually in an unfavorable sense; to diverge (L. di, apart, and vergo, incline, tend) is to turn from a course previously followed or that something else follows, and has no unfavorable implication; to digress (L. di, apart, aside, and gradior, step) is used only with reference to speaking or writing; to err is used of intellectual or moral action, and of the moral with primary reference to the intellectual, an error being viewed as in some degree due to ignorance. — from wander