懐旧[kaikyuu] recalling the old days
旧ソ連[kyuusoren] former Soviet Union
旧悪[kyuuaku] past misdeeds
旧衣[kyuui] worn-out clothes
旧詠[kyuuei] ancient poems

旧怨[kyuuen] old grudge
旧縁[kyuuen] old relationship
旧恩[kyuuon] old favors
旧仮名遣[kyuukanazukai] former (i.e. before the post-WWII reforms) kana usage in writing the readings of kanji

バナナの皮[banananokawa] banana peel
一皮[hitokawa] unmasking
化の皮[bakenokawa] masking one's true character
化けの皮をはぐ[bakenokawawohagu] to unmask (someone's true nature)
果皮[kahi] pericarp (ripened ovary wall forming part of a fruit)

外皮[gaihi] investment (in the sense of outer layer)
角皮[kakuhi] cuticle
桜皮[kanba] birch (esp. Japanese white birch)
乾皮[kanpi] dried hides
雁皮紙[ganpishi] traditional Japanese paper made from the fibre of plant species Diplomorpha sikokiana (high quality, glossy)

悪質[akushitsu] bad quality
悪質化[akushitsuka] worsening
異質[ishitsu] different (quality, nature)
音楽の素質[ongakunososhitsu] aptitude for music
音質[onshitsu] tone quality

可塑物質[kasobusshitsu] plastics
画質[gashitsu] image quality (film, video, etc.)
灰白質[kaihakushitsu] gray matter
企業体質[kigyoutaishitsu] financial content
器質的[kishitsuteki] organic