I am having a hard time with understanding why the word "врач" belongs to the second declension. The reason for that is that it's not obvious to me that the gender of врач is always masculine which is that subtle difference that keeps it from being a word of the third declension which implies different grammar rules. So my question is how do you people exactly know what the gender of a particular word is without looking it up in a dictionary?
In Russian, nouns do not decline for gender and hence do not agree with other nouns. The phrases like "она врач", "он тряпка", "он чудовище" etc. are perfectly grammatical.
Grammatical gender is an immanent property of a Russian noun (unlike, say, adjective which in Russian does decline for gender).
There is, however, an exception of so called common-gender nouns (умница, душка) etc. which, though still not changing their form being objects, make the adjectives defining them agree with the subject. Compare: он дикое животное / она дикое животное (the adjective agrees with the object), but он большой умница / она большая умница (the adjective agrees with the subject). However, the subjects themselves do not change their form.
It's quite easy to tell the declension of a noun knowing its spelling and gender, however, the words ending in
-ь may belong both to declensions II and III and you need to know their gender to tell them apart.
Even native speakers of Russian may have problems finding gender of the words лосось, тюль, шампунь, рояль etc. so you can find phrases like **вкусная лосось, **красивая тюль, **дорогая шампунь. This is a problem for nouns ending in
-ь preceded by a non-sibilant consonant, though may still be a problem for words ending in a sibilant consonant too if you don't know correct spelling (нож and дож are masculine while рожь and ложь are feminine).
The word путь, being masculine, currently declines according to declension III in all cases except instrumental. Until recently, the word день behaved the same.
This also may be a problem with declension I, however, masculine dec. I nouns are always animate and hence much easier to distinguish.
Finally, there are some masculine and neuter words ending in
-а constructed by adding the suffixes -ко, -ище, -ина and similar to masculine and neuter roots: умишко, человечище, доми́на.
Well, I'd rather disagree with Dima. In most cases it is quite obvious to which gender the noun belongs. Here are some empiric rules:
-aand '-я' ending indicates that noun is most probably feminine. Exceptions are given names like Коля, Петя and so on. Also, there is a group of nouns (бремя, время, вымя, знамя, имя, племя, пламя/полымя, семя, стремя, темя) which are neuter. Also, there are some words which easily can be guessed to be masculine, because of their usage, like
- Nouns with
-йending are most probably masculine. To be honest, I can not recall any exception.
- Most nouns with consonant (й is a consonant as well, its just that I can not recall any exclusion) endings are masculine.
Above-mentioned nouns with
-о/е/ёendings are likely to be neuter. Exceptions are some foreign words, which are usually masculine. The rule of thumb is following - if word is borrowing and it is indeclinable (
кафе), it is probably masculine. By the way, the same rule holds for borrowing with
пониetc. Though, for some of such words there is a clear tendency to become neuter, the most known case is
кофе. Some of such words, like
пальтоare already neuter. It won't be too bold oversimplification if we claim that the words which are more common and widely used tend to be neuter.
As for nouns with
эндшпильare masculine. Words
триольare feminine. But no one will judge you hard if you confuse gender in these words, because these cases are not that obvious even for some native speakers.
Any noun with
-жь/шь/чьending is feminine if in Genitive it ends with
If noun is in some way derivative (in a very wide sense) for some other word, sometimes this give you a hint. For example,
домишкоis related to
дом, so it is masculine.
Сулугуниis masculine since it a sort of cheese, and
cырis masculine, but
кольрабиis feminine, since it
капуста, as well as
салямиis feminine since it is actually
Авенюis associated with
улицаand so on.
жадинаcan be treated in different contexts as feminine or masculine. That means that there is no such word like
жадин. To be more precise such words are some times called common gender nouns (слова общего рода). Such words, helas, should be memorized.
Native speakers simply know from years of practice :). If you are learning the language you have to memorize the gender together with the word. This is just like memorizing German nouns together with the corresponding article that indicates its gender (der, die, or das). Or like memorizing the forms of irregular English words (take, took, taken; stand, stood, stood).
There are certainly patterns. Nouns ending with a consonant are most often masculine. Endings -о or -е usually mean "neuter". Endings -а, -я usually mean feminine. But there are lots of exceptions.
Actually even native speakers have difficulties with profession names like врач, инженер, академик etc. So they invent feminine gender for these words, which is not very simple in some cases: врачиха, инженерша. This is not correct, because in some cases these words already have different meaning (инженерша = жена инженера), but still they are used very often.