What is Go-hart?
1.
someone who goes the extra mile; i.e. an over-achiever. can also be spelt go-heart. stems from the term 'go-hard' which essentially means the same thing, but this is the mutated form of that word.
don't be such a go-hart
he's a real go-hart, he got like 99% on his test and was so pissed off
See
