障礙[shougai] obstacle
阻礙[sogai] obstruction
妨礙[bougai] disturbance
無礙[muge] free from obstacles

融通無礙[yuuzuumuge] free, unfettered and flexible
障礙者[shougaisha] (physically) handicapped person
縦横無礙[juuoumuge] being as free as the air

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