Prefix and Suffix

Today in class we played a "Suffix and Prefix" game.. They gave us a word and we have to choose the best option in prefix and suffix.. to created the whole word.. We learn how we can change totally the meaning of a word adding just a particle .. for example:

The word confortable.. means / Free from stress or anxiety; Producing feelings of ease or security /

But with the Prefix ' Un ' means ' Not '
so the word uncomfortable changed of meaning to / Experiencing physical discomfort; Causing anxiety; disquieting /