Hard-ass Definition

härdăs
hardass
noun
One who inflexibly follows or enforces rules.
American Heritage
One who is tough, inflexible, etc.
Webster's New World

(vulgar, slang) A tough and combative person.

Hopefully you don't take such a hard-ass approach as this.
Wiktionary

Alternative spelling of hard-ass.

Wiktionary
adjective
Tough, inflexible, etc.
Webster's New World