先入为主 - ChineseDict

xian1

先

ru4

入

wei2

为

為

zhu3

主

chengyu

(idiom) the first impression is the strongest; to hold a preconceived notion (about sth)

先 (先): beforehand; first; earlier; at first; originally; for the time being; for now; (prefix) my late (in referring to deceased relatives older than oneself)
入 (入): to enter; to go into; to join; to become a member of; to confirm or agree with; abbr. for 入聲|入声[ru4 sheng1]
为 (為): as (in the capacity of); to take sth as; to act as; to serve as; to behave as; to become; to be; to do; by (in the passive voice)
主 (主): owner; master; host; individual or party concerned; God; Lord; main; to indicate or signify; trump card (in card games)

Examples