suddenly and unexpectedly; "rain caught them unawares"; "sorrow comes to all, and to the young it comes with bittered agony because it takes them unawares"- A.Lincoln
without forethought or plan; inadvertently; "came upon the diamond unawares"
not subject to the control of the will; "involuntary manslaughter"; "involuntary servitude"; "an involuntary shudder"; "It (becoming a hero) was involuntary. They sank my boat"- John F.Kennedy
controlled by the autonomic nervous system; without conscious control; "involuntary muscles"; "gave an involuntary start"
characterized by undue haste and lack of thought or deliberation; "a hotheaded decision"; "liable to such impulsive acts as hugging strangers"; "an impetuous display of spending and gambling"; "madcap escapades"; (`brainish' is archaic)