commonest
com-mon-est
adjective
The superlative form of 'common', meaning most frequent, widespread, or ordinary.
"The sparrow is one of Britain's commonest birds."
Thesaurus
Synonyms: familiar, common, usual, ordinary, demotic, standard, frequent, grassroots, democratic, general, average, popular
Antonyms: case-by-case, individual, item-by-item, single, uncommon