IPA: /ˌrɛdʒɪˈsaɪdəl/
KK: /rɛˈdʒɪsɪdəl/
Relating to the act of killing a king or monarch.
The regicidal plot was discovered before it could be carried out.
Regicidal → It is formed from "regis" (from Latin, meaning king) and "-cide" (from Latin "caedere", meaning to kill). The word "regicidal" refers to the act of killing a king.
Think of the word 'regis' for king and '-cide' for kill — this helps you remember that regicidal means to kill a king.