The answer is:
DISREPUTABLE: not considered respectable in nature or looks.
Root: reput
Affixes:
dis-: prefix expressing negation.
-able: suffix meaning able to be or having the quality to.
The definition of a word is a statement with its exact meaning. The root of a word is the word in its basic form, with no affixes. Affixes are groups of letters attached to words which change their meaning, like prefixes and suffixes.