I'ven't
Contraction of I have not.
I'ven't seen a bigger act of beebery committed anywhere.
I'ven't
Abbreviation of I have not. Derived from I've and haven't.
I'ven't heard that one before.
Don't mind the smell, I'ven't had a shower in a week.
Don't mind the smell, I'ven't had a shower in a week.