"He needs a bigger jacket."
Translation:Ему нужна куртка побольше.
Only declinable adjectives are normally¹ put before the noun. Indeclinable adjectives are usually¹ put after nouns. Compare:
- Nominative: бе́жевые што́ры, што́ры беж,
- Genitive: бе́жевых што́р, што́р беж,
- Dative: бе́жевым што́рам, што́рам беж,
- Accusative: бе́жевые што́ры, што́ры беж (same as Nominative),
- Instrumental: бе́жевыми што́рами, што́рами беж,
- Prepositional: о бе́жевых што́рах, о што́рах беж.
Both бе́жевые што́ры and што́ры беж mean the same thing: 'beige curtains'. However, the adjective бе́жевый is declinable (it has different forms in different cases), so we put it before the noun. The (old-fashioned) adjective беж is indeclinable (it has the same form in all the cases), so we put it after the noun.
The form побо́льше is indeclinable, so we put it after the noun too:
- Nominative: ку́ртка побо́льше,
- Genitive: ку́ртки побо́льше,
- Dative: ку́ртке побо́льше,
- Accusative: ку́ртку побо́льше,
- Instrumental: ку́рткой побо́льше,
- Prepositional: о ку́ртке побо́льше.
¹ I say 'normally' and 'usually' because you can swap the normal word order for a stylistic effect. Such swapping usually draws attention to one of the words swapped. This is often used in poetry, but rarely used in ordinary speech. This is comparable to word order inversion in English.
побольше is more colloquial. And it is safe to say you'd more often use побольше and поменьше to mean bigger/smaller when requesting a different size of a garment. As for other comparative adjectives, по-prefixed variations are far more informal and are not taught in this course.
Again, for this use it is important to distinguish a comparative adjective uses as a modifier and a comparative adjective as a part of a predicate: "I bought a bigger chair" vs. "Your chair is bigger". In English it is rather easy because in a declarative sentence a form of a verb will separate a noun from an adjective that is not its modifier. Also, a modifier will come before a noun.
- note that when used as a modifier ("a bigger cup"), such adjectives are put after the noun in Russian.
Больше has other meanings, too (like, "more" or "bigger as a number"), which are not usually rendered with побольше. When comparing numbers or quantities, only больше is used. As an adverb or a comparative form of "много" /"мало" ( a lot / not a lot) we primarily use больше and меньше :
- Моя зарплата больше твоей ( or ", чем твоя") = My salary is bigger than yours.
- Вчера я купил больше, чем обычно (or "побольше", which is very informal) = Yesterday I bought more than usual.
- Миллион больше тысячи / меньше миллиарда = 10⁶ 10³ ( and 10⁹)
There are also adjectives бо́льший ("bigger") and ме́ньший ("smaller") that are primarily used in more abstract meanings and in set expressions. Think of something like "We managed to do it with smaller losses than we had expected" or "with an even bigger excitement", "a bigger number of people". They are not extremely formal, however, they are rarely used to refer to an object that is physically bigger /smaller. These are put before a noun, as any usual adjective.
Finally, there is an analytical way to form comparative adjectives (other than for "big" and "smaller"), It is to use the word "более" (more) or "менее" (less) and then a normal adjective: более высокий, более дорогой / менее высокий, менее дорогой. It is not how people usually speak but it is what you may find in A1-level textbooks (it is grammatical, just quite stiff for most everyday contexts). So do not be suprised to encounter something like Мой шарф более длинный, чем твой (My scarf is more long than yours).
- for "большой" such form would be extremely funny — we either use quite formal "больше" or less formal "побольше" after a noun.