tap / space
Classic usage
Estimated CEFR level: C2 — Proficiency
Estimated from word frequency; not an official CEFR classification.
From Middle English incertayne, borrowed from Middle French incertain, derived in the 14th c. from certain, after Latin incertus (“uncertain”). By surface analysis, in- + certain.
uncertain, unsure
Type a word, a sentence, a book title, or a link to an English article. WordNet and the Classics answer.
A library of classics · a vault of words · instant etymology & meaning
Sign in to use the worksheet generator.
Upload a file or open a document first.
One printable exam — questions numbered continuously with a single answer key. Only auto-gradable, closed-choice types are available; online auto-grading stays in Classroom.
Sign in to see your reading-vocabulary progress.
Your ledger is waiting
Read a chapter and tap the words you meet. Every word you learn is recorded here as your reading vocabulary grows.
—
Sign in to use vocabulary.
No vocabulary lists yet.
No matching vocabulary.
No words in this vocabulary yet.
Click a word in the Reader to add it.
Sign in to use bookmarks.
No bookmarks saved yet.
No matching bookmarks.
Sign in to save and open your own documents.
No saved documents yet.
Open a file or URL in the Reader, then use “Save to My Docs”.
All caught up — your streak is safe.
No cards due — add words to a list.
Loading…
tap / space
Classic usage
Loading…
Building today's round…
No tests yet. Open a book in the Reader or pick a vocabulary list, then test yourself to start tracking your score.
Recent books: 0 books
Verbault — Brown corpus levels, WordNet definitions, Gutenberg corpus.
Pick a puzzle source to start.
Sign in to use this source.