Is there a difference between болен and заболел or they are just synonyms? The context is "I am sick". (Я болен vs. Я заболел)

  • 1
    Болен - He's sick (now). Он заболел - He's sick (already).
    – Natty_Ras
    Commented Jul 23, 2017 at 7:52

6 Answers 6

  1. In most cases they are synonyms.
  2. Я болен means I am sick at the moment. (I am sick)
  3. Я заболел means I wasn't sick before, but now I am (I got sick)

The context:

-You don't look well. How are you? -Я болен.

-Why didn't you come to the party? Everybody was waiting for you! -Я заболел.


Grammatically, "болен" — is imperfect form (like "I'm ill") while "заболел" is perfect (like "I've caught cold"). Also "болен" is used in more serious or chronical cases, so if you want to tell your team that you want a sick-day, better choice would be "заболел".

  • 2
    It is the same kind of perfect/imperfect as in English tenses. In Russian most of verbs have several forms some of which are perfect and some are imperfect. I think you can consider it to be more or less same as changing tenses (present perfect instead of present simple and so on)
    – Alissa
    Commented Apr 25, 2017 at 12:08
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    Damn, sorry, болен is definitely not a verb. But not a noun as well.
    – Alissa
    Commented Apr 25, 2017 at 14:25
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    @Manjusri That usage is extremely rare nowadays, and frankly, I don't see how the confusion created by using it this way is justified, outside of the "gotcha" value it provides for pedantic posturing. Commented Apr 25, 2017 at 15:55
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    @Manjusri But that proves my point. A verbal noun like "description" or "walking" is still a substantive noun. Just like "описание" or "ходьба". And the more general question linked to quite unambiguously identifies nouns with nomina substantiva, not all nomina. Commented Apr 25, 2017 at 22:54
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    @Manjusri: did you maybe mean "nominal" en.wikipedia.org/wiki/Nominal_(linguistics) ? "Noun" is not a word which can be applied to adjectives.
    – Quassnoi
    Commented May 31, 2017 at 10:28

There's an important difference in meaning. Болен and больной can be used to say "mad", "nuts" while заболел is never used for this purpose.

Ты болен?! — Are you mad?!

Больной придурок! — Sick bastard!


Ты заболел?! — Have you become ill?! (e.g. caught a cold, flu etc., I'm worried about your health)

[Этот] придурок заболел! — This idiot became ill. (e.g. caught a cold, flu etc. and now we have problems because of his absence)

  • "mad" is more about enraged and aggressive, I guess. Better "are you nuts", or at least "are you crazy".
    – Arioch
    Commented May 30, 2017 at 15:54
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    @Arioch is correct. The meaning of "mad" has shifted from "insane" to "angry". English speakers will also be puzzled by the concept of "inadequate" conduct or an "inadequate" person. To them if something is inadequate, then more is needed.
    – David42
    Commented May 30, 2017 at 17:44
  • So it became specialised up to being but synonimous to "of inadequate quantity" ?
    – Arioch
    Commented May 30, 2017 at 17:55
  • And i'd say one can say "Ты, часом, не заболел?" as "You are coherent, aren't you?"
    – Arioch
    Commented May 30, 2017 at 17:58

Он болен <= He is sick,
Он заболел <= He became sick


Grammatically, болен is a noun on a bordeline between a Participle and an Adjective (from больной / болеть and in this sense it is close to verbal nouns in English) and заболел is a perfective verb (заболеть).

The difference is personal attitude / modality, as Alissa has already pointed out.

The other difference is that болен (as most of other shortened adjectives) are used for closing a topic, whereas заболел suggests further communication.

  • 1
    Could you please explain how a noun can be "between a Participle and an Adjective" According to Wikipedia: Noun is a thing, or a set of things. It's definitely far from Participles and Adjectives,
    – Vitaly
    Commented Apr 25, 2017 at 15:31
  • Pls. see the descriprion of имя as a linguistical term (not to be confused with "существительное"). dic.academic.ru/dic.nsf/es/77054/%D0%98%D0%9C%D0%AF
    – Manjusri
    Commented Apr 25, 2017 at 19:58
  • Болен cannot be a noun since it can change the gender: болен (masc.), больна (fem.), больно (neut.). Also, since it can function only as a predicative, it has no other cases beside nominative. The Russian verbal noun from the verb болеть are болезнь and боль.
    – Yellow Sky
    Commented Apr 26, 2017 at 14:58
  • Adjectives and participles are nouns (имена), for gods' sake!
    – Manjusri
    Commented Apr 27, 2017 at 20:09
  • @Manjusri No they're not. And frankly people here have at least as much cause to run out of patience with you and your pet theory as you do with them. Commented Apr 28, 2017 at 17:15

Болен can be used as a noun to mean illness. It's also used as a short-form adjective (Он болен. Она больна.) We would translate он заболел as he got sick.

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