りかい
理解 understanding comprehension

りかいりょく
理解力 (power of) understanding comprehensive faculty

りかいをふかめる
理解を深める to cultivate a better understanding

りかがく
理化学 physics and chemistry

りかく
離隔 isolation separation

りかだいがく
理科大学 college of science

りかにかんむりをたださず
李下に冠を正さず avoiding the appearance of evil don't straighten your crown under a pear tree (lit)

りかん
離間 estrangement alienation 罹患 contracting a disease

りかんさく
離間策 scheme to provoke discord or alienation

りかんりつ
罹患率 disease rate infection rate