てっきり

• Reading: てっきり
• Romaji: tekkiri
• Pronunciation: /tek.ki.ɾi/

Meaning

Surely; certainly; without a doubt. Expresses a firm belief that turns out to be wrong.

An adverb expressing a strong assumption or conviction, almost always used when that assumption proves incorrect. The typical pattern is てっきり…と思っていた (I was sure that…). Implies the speaker was completely convinced of something that turned out not to be true — てっきり来ると思っていた (I was sure you would come). Essential for expressing mistaken certainty in conversation.

Examples

1. てっきり彼が来ると思っていたのに来なかった。 I was sure he would come, but he didn't.
2. てっきり日本人だと思ったらアメリカ人だった。 I was convinced they were Japanese, but they turned out to be American.
3. てっきり冗談だと思っていたら本当だった。 I was sure it was a joke, but it was real.

Usage Guide

Context: daily life, conversation, storytelling

Tone: surprised

Origin & History

A native Japanese adverb, likely derived from an emphatic or intensifying expression. The double consonant っ adds force to the conviction, mirroring how certainty is felt strongly in the moment before being overturned.

Cultural Context

Era: Edo period

Generation: All ages

Social background: Universal