A sentence fragment is an incomplete sentence that lacks one of three necessary elements: a subject, a verb, or a complete thought. For example, "Because she was tired" contains both a subject and a verb; however, it does not have a main clause, leaving the reader waiting for the rest of the idea.
Sentence fragments frequently appear in first drafts and informal writing, and they can serve a stylistic purpose in creative writing. In formal writing, however, sentence fragments are generally considered grammatical errors. To fix a sentence fragment, either complete the thought by adding the missing element or join the fragment to a nearby sentence. For related grammar issues, see our guide on passive voice vs. active voice. Quetext's Grammar Checker flags sentence fragments automatically.