御食い初め[okuizome] weaning ceremony
為初め[shisome] outset
為初める[shisomeru] to begin to do
仮初[karisome] temporary
業界初[gyoukaihatsu] the industry's first ...

月初め[tsukihajime] beginning of month
最初[saisho] beginning
初めに[hajimeni] to begin with (used as an introduction)
初めは[hajimeha] at first
手初めに[tehajimeni] at first

其れ故に[soreyueni] and so ...
何故なら[nazenara] because
何故ならば[nazenaraba] because
エンジン故障[enjinkoshou] engine failure
縁故[enko] relation

何故かと言うと[nazekatoiuto] because
旧故[kyuuko] antiquity
故い[furui] old (not person)
故老[korou] old people

安全期[anzenki] safe period
暗黒期[ankokuki] eclipse period
一期[ichigo] one's life time
一期[ikki] one term
一期一会[ichigoichie] once-in-a-lifetime encounter (hence should be cherished as such)

一周期[isshuuki] period (in astronomy)
一定期間[itteikikan] fixed interval
延期[enki] postponement
延期になる[enkininaru] to be postponed
沖積期[chuusekiki] alluvial period

エンジン故障[enjinkoshou] engine failure
安全保障[anzenhoshou] security guarantee (e.g. military security, network security, etc.)
安全保障条約[anzenhoshoujouyaku] US-Japan Security Treaty
画障[gashou] pictured paper doors
気に障る[kinisawaru] to hurt one's feelings

気障[kiza] affected
血行障害[kekkoushougai] disturbance (blockage) of blood flow
故障[koshou] break-down
黒内障[kokunaishou] black cataract
差し障り[sashisawari] offence