Compound word adding Pump and Grunt. The act of pumping weights at an extraordinary volume. Loud enough so the entire gym will have no choice but to to take a glance out how "Jacked" and "Tan" you are.
A hardo is a person who tries extremely hard at everything. Most times a hardo will try very hard at things that do not require excessive effort. For example, sports practices, gym class, etc.
Wow did you see Jack at practice today? What a hardo!