Expression of terror, awe, surprise, shock, etc., often at something seen for the first time or remembered immediately before using this term
'Holy shit, that car just exploded!''.
Shit is a vulgar word in Modern English denoting feces (faeces). It is a native English word, but Latin terms for many common objects and bodily functions came to be seen as more distinguished than native words, and thereafter feces became the accepted English noun, to defecate became the accepted English verb, and shit was no longer used in polite company