Idiom

An idiom is a common word or phrase with a culturally understood meaning that differs from what its composite words' denotations would suggest; i.e. the words together have a meaning that is different from the dictionary definitions of the individual words.

By another definition, an idiom is a speech form or an expression of a given language that is peculiar to itself grammatically or cannot be understood from the individual meanings of its elements.

For example, an English speaker would understand the phrase "kick the bucket" to mean "to die" – and also to actually kick a bucket. Furthermore, they would understand when each meaning is being used in context.

C2 | Proficiency

C2, also called Proficiency, is the highest level on the CEFR scale. Reaching this level means you can understand and produce English with near-native command — not just accurately, but with nuance, precision, and ease across virtually any context.

What C2 looks like in practice

At this level, you are expected to:

• Understand with ease virtually everything you hear or read, including abstract, structurally complex, or highly colloquial material.
• Express yourself spontaneously and precisely, choosing words that capture finer shades of meaning — even in unfamiliar or high-pressure situations.
• Produce clear, well-structured text on complex subjects, with controlled use of organizational patterns, connectors, and cohesive devices.
• Recognize implicit meaning in demanding, longer texts — picking up on irony, understatement, and unstated assumptions.
• Communicate fluently without noticeable searching for expressions, adapting your register naturally to academic, professional, or informal settings.

How C2 differs from C1

While a C1-level user handles complex language competently, a C2 user does so effortlessly and with subtlety. The difference often shows up in:

• Idiomatic range — C2 users draw on a full repertoire of idiomatic expressions, colloquialisms, and cultural references.
• Precision under pressure — they can reformulate, hedge, or sharpen their point in real time without losing fluency.
• Writing sophistication — their texts read as polished and naturally organized, not just grammatically correct.

In short, C2 is less about learning new grammar rules and more about mastering the flexible, context-sensitive use of everything you already know.

Test your level

If you think you're approaching C2, try one of these challenges to check:

• CEFR C1/Advanced – check if this is your English grammar mastery level
• Pass the Test to Determine Your English CEFR Level

C1 | Advanced

C1 is the fifth of six levels in the Common European Framework of Reference for Languages (CEFR), sitting between B2 (Upper-Intermediate) and C2 (Proficiency). It's classified as Advanced — the stage where you stop translating in your head and start thinking in English.

What a C1 user can do

At this level, you're expected to handle complex, demanding language across a wide range of situations:

• Reading — You can understand long, complex texts, including specialized articles and technical instructions outside your own field. You pick up on implicit meaning, not just what's stated directly.
• Speaking — You express yourself fluently and spontaneously with minimal searching for words. You use language flexibly for social, academic, and professional purposes.
• Writing — You produce clear, well-structured, detailed text on complex subjects, with controlled use of organizational patterns, connectors, and cohesive devices.
• Listening — You follow extended speech even when it isn't clearly structured or when relationships between ideas are only implied.

What C1 grammar looks like

C1-level grammar goes well beyond accuracy with tenses and articles. You're expected to use advanced structures naturally, including:

• Inversion for emphasis (Rarely have I seen such dedication.)
• Mixed and advanced conditionals (Had she known, she would never have agreed.)
• Subjunctive forms in formal contexts (It's essential that he be informed.)
• Cleft sentences for focus (What concerns me is the timeline.)
• Complex noun phrases and nominalization (The government's repeated failure to act…)

The difference between B2 and C1 isn't just knowing these structures exist — it's using them appropriately and with control across different registers.

Self-check: If you can read an opinion piece in The Guardian or The Economist and follow the argument without a dictionary, and if you can write a structured response disagreeing with it, you're likely operating at C1.

How C1 fits in the CEFR scale

The CEFR has six levels: A1 → A2 → B1 → B2 → C1 → C2. C1 is where most universities and professional bodies set their language requirements for non-native speakers.

Ready to test yourself? Try Pass the Test to Determine Your English CEFR Level or go straight to the C1/C2-level test. You can also practice key C1 structures like Inversion and Conditional Subjunctive.

Difficulty: Hard

Hard difficulty. Difficulty levels represent author's opinion about how hard a question or challenge is.