scare the hell out of someone meaning

[American slang]
tr. to frighten someone badly. (Use caution with hell.)
• These figures scare the hell out of me.
• The door blew shut and scared the hell out of me.

• scare someone stiff:    [American idiom]to ...
• scare someone to death:    [American idiom]to ...
• scare the pants off someone:    [American slang]tr ...