obviate( /??bv?e?t / ) the need for 使無必要

ob詞根→against

viate詞根→go，如via,deviate(偏離)(de詞綴表away)

→go against 理解為把前進(jìn)路上的障礙去除掉

nullify→/?n?l?f?? / to make a legal agreement or decision have no legal force.

negate→/n??ɡe?t/ to cause something to have no effect.

eg: The increase in our profits has been negated by the rising costs of running the business.