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

閾値[ikichi] threshold (amount, dose, etc.)
識閾[shikiiki] threshold of consciousness
閾下[ikika] subliminal (below the threshold of sensation or consciousness)
閾刺激[ikishigeki] threshold stimulus

検知閾値[kenchiikichi] detection threshold
痛覚閾値[tsuukakuikichi] pain threshold
閾値下[ikichika] subliminal