Part of speech: Adverb
without favoring one party, in a fair evenhanded manner
Example: deal fairly with one another
Part of speech: Adverb
in conformity with the rules or laws and without fraud or cheating
Example: they played fairly
Passably, Fair, Evenhandedly, Pretty, Reasonably
Unreasonably, Unfairly, Immoderately
The word "fairly" comes from Middle English fayrly.
fair – A related word in the same word family.
ly – A related word in the same word family.
Many Middle English words had multiple spellings because standardization didn't exist yet.