Misspend
/ˌmɪsˈspend/
Definition 1 of 1
Pro Tip 1/3Negative Connotation
Carries a judgemental tone, suggests poor judgement or improper behavior. 
The charity faced criticism for misspending donations.
Pro Tip 2/3Casual Tone
Often used in informal contexts to criticize or regret past actions. 
Looking back, I misspent so much time playing video games.
Pro Tip 3/3Personal Regret
Can express personal remorse over misuse of personal resources. 
I misspent my inheritance within a year and regretted it.