安危[anki] fate
危うい[ayaui] dangerous
危うく[ayauku] barely
危ない[abunai] dangerous
危ながる[abunagaru] to be afraid of

危なっかしい[abunakkashii] dangerous
危ぶむ[ayabumu] to fear
危める[ayameru] to wound
危絵[abunae] suggestive or indecent picture
危害[kigai] injury

井の中の蛙大海を知らず[inonakanokawazutaikaiwoshirazu] parochial
雨蛙[amagaeru] tree frog (esp. the Japanese tree frog, Hyla japonica)
蛙の子は蛙[kaerunokohakaeru] like father, like son
蛙跳び[kaerutobi] (game of) leapfrog
殿様蛙[tonosamagaeru] black-spotted pond frog (Rana nigromaculata)

蟇蛙[hikigaeru] toad (esp. the Japanese toad, Bufo japonicus)
蛙又[kaerumata] curved wooden support on top of the main beam of a house, now mainly decorative (shape evocates an open-legged frog)
青蛙[aogaeru] green (tree) frog
赤蛙[akagaeru] any brown or reddish-brown frog (esp. of family Ranidae)