WordNet

small Australian bird related to the button quail; classified as wading bird but inhabits plains (同)Pedionomus torquatus
not elaborate or elaborated; simple; "plain food"; "stuck to the plain facts"; "a plain blue suit"; "a plain rectangular brick building"
extensive tract of level open land; "they emerged from the woods onto a vast open plain"; "he longed for the fields of his youth" (同)field, champaign
lacking embellishment or ornamentation; "a plain hair style"; "unembellished white walls"; "functional architecture featuring stark unornamented concrete" (同)bare, spare, unembellished, unornamented
not mixed with extraneous elements; "plain water"; "sheer wine"; "not an unmixed blessing" (同)sheer, unmingled, unmixed
lacking patterns especially in color (同)unpatterned
free from any effort to soften to disguise; "the plain and unvarnished truth"; "the unvarnished candor of old people and children" (同)unvarnished
go via an indirect route or at no set pace; "After dinner, we wandered into town"
someone who leads a wandering unsettled life (同)roamer, rover, bird_of_passage

PrepTutorEJDIC

『はっきり見える』(『聞こえる』) / 『はっきり理解できる』,明白な / 全くの(sheer) / 混ぜ物のない,生(き)のままの;飾りのない;無地の / ありのままの / 『質素な』,飾り(模様)のない / (食べ物が)淡白な / 平凡な,並みの,普通の;素朴な / 『平原』,平野;《the Great Plains》(北米の)大平原地帯
(編みもので)平編みの,基本編みで作った / 平編み,基本編み
《方向・場所を表す副詞[句]を伴って》『あてもなく歩き回る』,さまよう / (道・主題から)『それる』,はずれる,脱線する《+from(off)+名》 / 〈考え・言葉などが〉乱れる,取り留めがなくなる / 〈山・川・道などが〉曲がりくねる / …‘を'さまよい歩く,ぶらつく
放浪者,さすらう人