What is the meaning of Slap_in_the_face?

Used other than figuratively or idiomatically: see slap, in, the, face. (This sense is a translation hub.)

Something unexpectedly said or done which causes shock or offense; an insult, rebuke, or rebuff.

To insult or offend unnecessarily.

To be or suddenly become bluntly obvious to.

Source: wiktionary.org