CURIOUSER AND CURIOUSER

Joseph Appel

The prefix IN means NOT, as in INCORRECT, INACTIVE, and thousands of other words. However, the words VALUABLE and FLAMMABLE do not change meaning when preceded by IN. INVALUABLE still means valuable, and INFLAMMABLE still means flammable. 

Can you think of a word with the suffixes FUL and LESS, in which the meaning of the word does not change even though it has opposite suffixes?

Answer:

The word is SHAME, as in  SHAMEFUL AND SHAMELESS.

When a person is accused of being shameless, it means he should be ashamed (shameful).