不悪[ashikarazu] don't get me wrong, but ...
意識不明[ishikifumei] unconscious
一心不乱[isshinfuran] wholeheartedly
一定不変[itteifuhen] invariable
運動不足[undoubusoku] insufficient exercise

栄養不足[eiyoubusoku] malnutrition
過不足[kafusoku] excess or deficiency
回復不可能[kaifukufukanou] non-recoverable
気不味い[kimazui] unpleasant
健康不安[kenkoufuan] poor health

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

敵わない[kanawanai] no match for
怨敵[onteki] sworn enemy
外敵[gaiteki] foreign enemy
敵う[kanau] to come true (wish)
仇敵[kyuuteki] bitter enemy

敵討[katakiuchi] vengeance
敵同士[tekidoushi] mutual enemies
旧敵[kyuuteki] old enemy
強敵[kyouteki] formidable enemy
公敵[kouteki] public enemy

臥薪嘗胆[gashinshoutan] going through thick and thin to attain one's objective
魂胆[kontan] soul
大胆[daitan] bold
胆汁[tanjuu] bile
胆石[tanseki] gallstones

胆のう[tannou] gall bladder
胆力[tanryoku] courage
度胆を抜く[dogimowonuku] to knock or scare (someone) out of his or her wits
落胆[rakutan] discouragement