snuck

Both snuck and sneaked are acceptable past tense forms of the verb sneak.

Historically, sneaked (which is older) has been the more widely accepted version, with snuck being considered nonstandard, but snuck has a long history of use and is now very common.

Sneaked uses the regular past tense ending -ed, while snuck is an irregular verb. Irregular verbs don’t follow a set pattern in the forms of their different tenses, as in take/took/taken and sing/sang/sung.

Sneaked is more commonly used (and often preferred) in more formal contexts (though the word sneak itself can sound a bit informal).

Here are examples of how snuck and sneaked can be used interchangeably.

Example with snuck: When I was a kid, I once snuck into a movie theater, but I got caught.

Example with sneaked: When I was a kid, I once sneaked into a movie theater, but I got caught.

Want to learn more? Read the full breakdown of the difference between snuck and sneaked.

Would it be acceptable to use either snuck or sneaked in the following sentence?

He _____ back into the building to steal the documents.