窮屈 （キュウクツ） narrow, tight, cramped, formal, stiff, strict, ceremonious, rigid, constrained, uncomfortable, tight (e.g. finances)

究極 （キュウキョク） ultimate, final, last, eventual

無窮 （ムキュウ） eternity, infinitude, immortality

天壌無窮 （テンジョウムキュウ） as eternal as heaven and earth

極める （きわめる） to carry to extremes, to go to the end of something, to reach the limits of something, to reach the peak of something (e.g. luxury, hardships, etc), to be extremely (e.g. busy), to exhaust completely, to have nothing left (e.g. to say)

極まる （きわまる） to reach an extreme, to reach a limit, to terminate, to come to an end, extremely, to be stuck, to be in a dilemma, to be at a loss, to be decided, to be settled

極まり （きわまり） extremity, end, bound, limit

極まりない （きわまりない） extremely, in the extreme, knows no bounds (e.g. rudeness), unparalleled, boundless (e.g. universe, ocean), limitless

極み （きわみ） height, acme, extremity, peak, end, limit

窮みなき （きわみなき） without limit, endless