A synonym
The word that matches the definition of a small hill or mound is "knoll."
light
The definition that best matches the use of the word "fumed" is: to show irritation or anger by emitting smoke, fumes, or vapors.
The word that matches the definition of moral rightness is "integrity." Integrity refers to the quality of being honest and having strong moral principles.
reduce
you can go to dictionary.com
Avoid
Certainly, please provide the root word and its definition so that I can offer you an appropriate prefix.
A landfill.
constitution
If referring to a person - 'prominent' , 'celebrated' .