STUMPERS LXX
Credit: GAMES Magazine - Dec. 2000
Alvin M. Sanico
IN- CONSISTENT TERMS? (#1)

1. Adding the prefix "IN" to a word usually creates a new word that's the opposite of the original - (capable - incapable, decisive - indecisive). But can you think of two common adjectives whose meanings remain basically unchanged when preceded by IN?

2. Can you think of a common verb whose meaning stays the same when preceded by UN?

Answers:

1. The words are VALUABLE and FLAMMABLE.

In common usage, they are used interchangeably with INVALUABLE and INFLAMMABLE. 

2. THAW

THAW and UNTHAW can be used interchangeablly.