The practice of trying to spend as little money as possible

吝嗇

Acting with or showing care and thought for the future.

保守

Using money and other resources carefully and not wastefully.

節約

Sparing or economical as regards money or food

節儉

Reserved (adj.)

Slow to reveal emotion or opinions

內斂, 含蓄

Bashful (adj.)

Reluctant to draw attention to oneself; shy.

靦腆

Timid (adj.)

Showing a lack of courage or confidence; easily frightened.

膽小的，膽怯的

Diffident (adj)

Modest or shy because of a lack of self-confidence.

羞怯的/ 沒自信的

Introverted (adj.)

An introvert is a person with qualities of a personality type known as introversion, which means that they feel more comfortable focusing on their inner thoughts and ideas, rather than what's happening externally.

內向

In a state of wild excitement or ecstasy.

極度興奮