감

Feeling 

감 = feeling
감정 = feeling, emotion
민감하다 = sensitive
감사하다 = thank
감동(하다) = deep impression, be moved
감각 = sense
공감(하다) = sympathy, sympathise
자신감 = confidence
열등감 = sense of inferiority 

Watch

감독하다 = supervise, oversee
감시(하다) = keep an eye, keep close watch on
감옥 = prison 

Decrease

감소(하다) = decrease
감량(하다 = loss of quantity
삭감(하다) = reduction, cut down
감봉(하다) = salary reduction