お大事に[odaijini] take care of yourself
暗黒大陸[ankokutairiku] Dark Continent (i.e. Africa)
伊勢大神宮[isedaijinguu] the Grand Shrines of Ise
伊勢大廟[isetaibyou] the Grand Shrines of Ise
偉大[idai] greatness

医科大学[ikadaigaku] medical school
医大[idai] medical university
井の中の蛙大海を知らず[inonakanokawazutaikaiwoshirazu] parochial
一大[ichidai] one large ...
一大事[ichidaiji] serious affair

亜綱[akou] (biological) subclass
井戸綱[idozuna] well rope
井綱[izuna] well rope
横綱[yokozuna] yokozuna (grand champion)
綱曳き[tsunahiki] tug of war (orig. a form of divination to predict whether the year will be favourable or unfavourable)

綱紀[kouki] law and order
綱紀粛正[koukishukusei] eliminating corruption among government officials
綱渡り[tsunawatari] tightrope walking
綱要[kouyou] elements