Upset is an irregular verb. Its past tense form (upset) must be memorized as it does not follow standard conjugation rules.
Verbs that follow a similar irregular pattern to upset:
| Base | Past Tense | Pattern |
|---|
Upset is irregular. Its past tense (upset) must be memorized.
Use past time markers: "Yesterday, she upset to the store."
No. Use "did not upset" (not "did not upset").
The verb upset is an irregular verb in English. Unlike regular verbs that simply add -ed, upset changes to upset in the past tense. This irregular form must be memorized as it does not follow the standard conjugation rules.
Irregular verbs like upset/upset trace back to Old English strong verbs, where vowel changes (ablaut) indicated tense shifts. Over centuries, most verbs regularized to the -ed pattern, but the most frequently used verbs retained their irregular forms because they were too common to change. This is why go/went, see/saw, and break/broke remain irregular today.
When using upset in writing, remember that it functions as a past tense verb and typically appears with time markers like yesterday, last week, or ago. For example: "Yesterday, she upset to the store." The past tense form does not change based on the subject — I upset, you upset, he/she upset, we upset, they upset.