Nouns

(n)square, foursquare(geometry) a plane rectangle with four equal sides and four right angles; a four-sided regular polygon“you can compute the area of a square if you know the length of its sides”

Adjectives

(s)foursquarecharacterized by firm and unwavering conviction“a foursquare refusal to yield”

Adverbs

(r)foursquarein a square position“the building stood foursquare”
(r)squarely, foursquare, straightforwardlywith firmness and conviction; without compromise“he stood foursquare for religious liberty and toleration” (C.G.Bowers), “dealt straightforwardly with all issues”