causeless

We stood staring after the fugitives in perfect bewilderment, totally unable to explain their apparently causeless panic.

At Lockmaben he took an equally causeless alarm from a still slighter circumstance.

After Chickamauga, there was very general—and seemingly not causeless—discontent.

Do you know, do you see, my dearest life, what appearances your causeless apprehensions have given you?

My heart rises against thee, O thou cruel implement of my brother's causeless vengeance.