Definitions:

1. A stupid or incompetent person. NOUN
   • Only a jackass would make such a silly mistake.
2. Refers to someone who behaves in a silly or annoying manner, often without regard for the consequences or feelings of others. NOUN
   • His cocky attitude makes him come across as a real jackass sometimes.
3. Typically refers to a male donkey. NOUN
4. Used to describe a foolish or obnoxious person. NOUN
   • Quit acting like a jackass and take responsibility for your actions.

Synonyms:

• cuckoo
• delt
• donkey
• fool
• goofball
• idiot
• jack
• ninny