お七夜[oshichiya] name-giving ceremony
七つ[nanatsu] seven
七つの海[nanatsunoumi] the seven seas
七屋[nanatsuya] pawnshop
七回忌[shichikaiki] seventh anniversary of a death

七角形[shichikakkei] heptagon
七曲がり[nanamagari] tortuous or spiral (path)
七月[shichigatsu] July
七賢[shichiken] the Seven Wise Men (of Confucius's Analects)

し難い[shinikui] hard to do
一難[ichinan] one difficulty
火難[kanan] fire calamity
海難[kainan] shipwreck
患難[kannan] affliction

危難[kinan] peril
及び難い[oyobigatai] hard to attain to
救難[kyuunan] rescue
救難ヘリコプター[kyuunanherikoputaa] rescue helicopter
苦難[kunan] suffering