power, authority

(いきおい) Momentum, the power to influence something – like, “The car had a lot of 勢い so it was hard to stop the car before we hit the cat” or “Because of the whiskey’s 勢い, I could do a table dance in the White House.” Also means to gain steam or lose steam – said of political momentum or the momentum of a trend or ideology.
(ちから) Force or strength (of a person but also of a thing – tidal wave, lightning, mighty rhino, etc.)
(けんりょく) Power (over other people)(as in boss, parent, governor, pope, etc.)
(いりょく) Power in a bad way- scary power. Like the power of heroin or the power of a corrupt cop. Not very useful.
(せいけん) Political power.
(けんり) The right to do something.
(けんい) An authority one has based on power alone (parents, cops, etc.) rather than on rights (like the related word 権利(けんり))