a. 未奉命的, 未受指使的, 自发的, 未受邀请的

Unbid \Un*bid"\, Unbidden \Un*bid"den\, a.
1. Not bidden; not commanded.

Thorns also and thistles it shall bring thee forth
Unbid; and thou shalt eat the herb of the field.
--Milton.

2. Uninvited; as, unbidden guests. --Shak.

3. Being without a prayer. [Obs.] --Spenser.