に当たって[niatatte] at the time of (ind. opportunity or situation where something should be done)
一騎当千[ikkitousen] being a match for a thousand
一指当たり[ichiyubiatari] span
一人当たり[hitoriatari] per person
一人当て[hitoriate] per person

引当[hikiate] mortgage
引当金[hikiatekin] reserves
押し当てる[oshiateru] to push (something) against
穏当[ontou] proper
過当[katou] excessive

威張り散らす[ibarichirasu] to domineer
胃散[isan] stomach medicine
逸散に[issanni] at top speed
一目散[ichimokusan] at full speed
一目散に[ichimokusanni] at full speed

雲散霧消[unsanmushou] vanishing like mist
解散[kaisan] breakup
拡散[kakusan] scattering
閑散[kansan] deserted (esp. store, market, town, streets)
言散らす[iichirasu] to spread (a report)