A thesaurus is most helpful for students who must find the correct pronunciation for a difficult new word.
need to find multiple definitions for one word.
would like to keep their writing from becoming repetitive.
are looking for multiple forms of one word.

Syllable added to a root word to change its meaning : affixan independent word--example run,walk,book : free morphemeaffix that gives grammatical meaning such as tense or number : inflectiona word part that must attach to a word in order to be usable : bound morphemedegree of comparison formed by adding -er or more to an adjective : comparativedegree of comparison formed by adding -est or most to an adjective : superlativeaffix added to the beginning of a word : prefixaffix added to the end of a word : suffixroot word of lovable : lovetwo roots used together to form one word : combining form

Slap.without warning, the gorilla hit the glass of his enclosure. tourist dropped their cameras.