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

遺蹟[iseki] historic ruins (remains, relics)
筆蹟[fudeato] handwriting
偉蹟[iseki] remaining works
奇蹟[kiseki] miracle
史蹟[shiseki] historical landmark

真蹟[shinseki] true autograph
事蹟[jiseki] evidence
古蹟[furuato] historic spot
城蹟[joushi] castle site
手蹟[shuseki] holograph