IPA: /suˈaɪdəl/
KK: /suˈaɪdəl/
Relating to or having thoughts about taking one's own life; often associated with feelings of extreme sadness or hopelessness.
He was feeling suicidal and needed to talk to someone about his feelings.
Suicidal → It is formed from "sui-" (from Latin "sui", meaning of oneself) and "-cidium" (from Latin "caedere", meaning to kill). The word "suicidal" refers to the act of killing oneself, hence relating to one's own self.
Think of 'sui' meaning 'of oneself' and 'caedere' meaning 'to kill' — this helps you remember that 'suicidal' relates to the act of harming oneself.