Definition from Wiktionary, the free dictionary
- Pertaining to suicide.
- He is an authority on the precursors of suicidal behavior.
- (of a person) Likely to commit, or to attempt to commit, suicide.
- After losing his job, his wife, and his leg in a single week, he became suicidal.
- (informal) Extremely reckless.
- His driving habits are utterly suicidal.
Related terms 
pertaining to suicide
likely to commit, or to attempt to commit, suicide
suicidal (plural suicidals)
- someone suicidal, someone likely to kill themselves