Verb
shun - To persistently avoid, ignore, or reject (someone or something) through antipathy or caution

When David tried to join in the conversation at the club, they ignored him, and he suspected that he was being shunned because he had a different religion than they did.
tinker - To attempt to repair or improve something in a casual way, often to no useful effect

Mitch tried to tinker with his computer before realizing that it was more broken that he had thought, and that he had to bring it to the computer store to have a professional repair it.