Disturb, v. t. [imp. & p. p. Disturbed; p. pr. & vb. n. Disturbing.] — Webster enters it under “disturb”
Etymology: [OE. desturben, destourben, OF. destorber, desturber, destourber, fr. L. disturbare, disturbatum; dis- + turbare to disturb, trouble, turba disorder, tumult, crowd. See Turbid.]
1. To throw into disorder or confusion; to derange; to interrupt the settled state of; to excite from a state of rest. Preparing to disturb With all-cofounding war the realms above. Cowper. The bellow's noise disturbed his quiet rest. Spenser. The utmost which the discontented colonies could do, was to disturb authority. Burke.
2. To agitate the mind of; to deprive of tranquillity; to disquiet; to render uneasy; as, a person is disturbed by receiving an insult, or his mind is disturbed by envy.
3. To turn from a regular or designed course. [Obs.] And disturb His inmost counsels from their destined aim. Milton.
Syn. -- To disorder; disquiet; agitate; discompose; molest; perplex; trouble; incommode; ruffle.
1 other Webster entry under this spelling
Disturb, n.
Disturbance. [Obs.] Milton.
Shades of meaning
Fernald lists disturbed only as an antonym, under calm.
He lists it without comment; the entries above explain its neighbors.