A hardass or hard ass
is someone who is very authoritative or who appears to be such. This type of person will have his or her own way and expects the respect and co-operation of others.
This is someone who won't let you get away with anything. Someone who falls into this category usually offers a lot of tough love and tends to lack empathy for other people.
As long as you show a good level of respect in a hardass' presence, you should be fine. They prey on teenagers and those who are feeble-minded.
Person 1: Oh man, my dad's such a hardass.
Person 2: Yeah, what did he do?
Person 1: He kicked me out of the house and enrolled me in the army just for skipping one class.
Person 2: Shiiiit! WHAT a hardass.
Person 1: Duuuude, I know.