Cool MateForbidden vs Illegal vs Unconstitutional
When to use each in English, with meaning, register, and examples.
Forbidden
FormalTop 3,000 (common)
Illegal
FormalTop 2,000 (common)B1adjective
Unconstitutional
FormalBeyond 10,000 (less common)B1adjective
Most common: Illegal
| Forbidden | Illegal | Unconstitutional | |
|---|---|---|---|
| Pronunciation | 🇬🇧 //fəˈbɪd.ən//🇺🇸 //fərˈbɪd.ən// | 🇬🇧 //ɪˈliːɡ(ə)l//🇺🇸 //ɪˈlɪɡəl// | 🇬🇧 /["/ˌʌnˌkɒnstɪˈtjuːʃənl/"]/🇺🇸 /["/ˌʌnˌkɑːnstɪˈtuːʃənl/"]/ |
| Meaning | Not allowed or banned. | Not allowed by law. | Not allowed by the constitution of a country. |
| Example | The secret room was strictly forbidden to anyone except the owner. | Driving without a license is considered illegal. | The judges declared the decision unconstitutional. |
| Register | Formal | Formal | Formal |
| How common | Top 3,000 (common) | Top 2,000 (common) | Beyond 10,000 (less common) |
| CEFR level | - | B1 | B1 |
| Part of speech | adjective | adjective | |
| Collocations | forbidden zone, forbidden love, forbidden activities, forbidden fruit, forbidden city | illegal activity, illegal immigration, illegal drugs, illegal parking | unconstitutional law, unconstitutional action, declare unconstitutional |
| Antonyms | allowed, permitted, legal | legal, permissible, lawful | constitutional, legal |
| Common mistakes | Confused with 'prohibited' - both mean similar things, but 'forbidden' is less formal., Incorrectly used as a verb - 'forbidden' is strictly an adjective., Using 'forbidden' in positive contexts - it always suggests something disallowed. | Confused with 'unlawful', which can have a broader meaning., Using 'illegal' to describe moral wrongs instead of legal ones., Misusing as a noun instead of an adjective, e.g., saying 'the illegal is punishable' instead of 'the act is illegal'. | Confused with 'illegitimate' when they are not exactly the same., Using it in non-legal contexts., Incorrectly conjugating as a verb. |
| Usage notes | Used to describe something that is legally or socially unacceptable. Avoid using in casual conversations. | Use 'illegal' in formal contexts, especially legal discussions, but also in general conversation. It's not appropriate for casual slang. | Use 'unconstitutional' in legal and formal contexts when referring to laws or actions that violate a constitution. Avoid in casual conversations. |
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Frequently asked questions: Forbidden vs Illegal vs Unconstitutional
What's the difference between Forbidden, Illegal, and Unconstitutional?
Forbidden: Not allowed or banned. Illegal: Not allowed by law. Unconstitutional: Not allowed by the constitution of a country.
Which is more common: Forbidden, Illegal, and Unconstitutional?
Illegal is the most common in everyday English.
Can you show an example of each?
Forbidden: The secret room was strictly forbidden to anyone except the owner. Illegal: Driving without a license is considered illegal. Unconstitutional: The judges declared the decision unconstitutional.
Can I use Forbidden, Illegal, and Unconstitutional interchangeably?
Not always. Forbidden, Illegal, and Unconstitutional are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.