1. addled = confused
2. back out = withdraw from
3. flip out = to lose self-control
4. gag = a joke
5. pen = prison (short for penitentiary)
6. shaft = cruel treatment
Slang words are considered to be informal, and should thus only be used in informal situations, for example, when talking to your friends. When in formal situations, only their formal counterparts should be used.
