Latin word securus comes from Latin se- (Separately, astray. Without.), Latin curam

Detailed word origin of securus

Dictionary entry	Language	Definition
se-	Latin (lat)	Separately, astray. Without.
curam	Latin (lat)
securus	Latin (lat)	Careless, negligent. Fearless. Quiet, composed, serene. Unconcerned, untroubled, carefree.