以为

• Pinyin: yǐ wéi
• Hanzi breakdown: 以 = ancient character meaning 'to use'; 为 = simplified from 為, meaning 'to be/do'

Meaning

To think (mistakenly); to assume wrongly. Indicates a belief that turns out to be incorrect.

Unlike 认为 (to think/believe), 以为 implies the thought or assumption was wrong. Very commonly used in daily conversation to express a mistaken belief or expectation. Often followed by a correction with 原来 or 其实.

Examples

1. 我以为你不来了，原来你来了。 I thought you weren't coming, but here you are.
2. 他以为今天不上课，结果迟到了。 He assumed there was no class today and ended up being late.
3. 我以为这道菜很辣，其实不辣。 I thought this dish was very spicy, but it actually isn't.

Usage Guide

Context: everyday, conversation

Tone: neutral

Do Say

• 我以为他是老师，原来是学生。(I thought he was a teacher, but he's actually a student.)
• 别以为我不知道。(Don't think I don't know.)

Don't Say

• 我以为地球是圆的。(Don't use 以为 for correct beliefs — since 以为 implies being wrong, use 认为 or 觉得 for accurate opinions.)

Origin & History

Compound of 以 (to use/take) and 为 (to be/consider as), literally 'to take as' — implying a subjective assumption.

Cultural Context

Generation: All ages

Social background: Universal