Too strong to be defeated or overcome; invincible.
Of a fortress or other fortified place: able to withstand all attacks; impenetrable, inconquerable, unvanquishable.
Capable of being impregnated; impregnatable.
Extremely reckless.
Likely to commit, or to attempt to commit, suicide.
Highly likely to certain to result in the deaths of the participants; dangerous or reckless to such a degree as to be tantamount to suicide for those taking part.
Pertaining to suicide.
Someone suicidal; someone likely to kill themselves.