The article goes on the first word
A Romanian noun carries its definite article as an ending: profesorul, casa. That ending always sits on the FIRST word of the phrase. So when an adjective moves in front of the noun, the article moves onto the adjective: noul profesor (the new teacher), frumoasa casă (the beautiful house). The noun after it stays bare: never noul profesorul. You have known one example since your first weeks: micul dejun (breakfast) is mic + the article, in front of dejun.
| adjective after | adjective in front |
|---|
| profesorul nou | noul profesor |
| casa frumoasă | frumoasa casă |
| doctorul bătrân | bătrânul doctor |
| colegii noi | noii colegi |
| cărțile noi | noile cărți |
An adjective in -e takes -le, like a noun in -e: mare → marele scriitor (feminine marea). After un, o, acest or acel nothing changes: un nou coleg, acest mare om.
The case ending moves too
In the genitive and the dative the ending also goes on the adjective, and the noun still stays bare:
| nominative | genitive / dative |
|---|
| masculine | noul profesor | noului profesor |
| feminine | frumoasa casă | frumoasei case |
| plural | noii colegi | noilor colegi |
A possessive comes straight after the adjective: noul nostru vecin, buna mea prietenă.
Why put it first?
Profesorul nou and noul profesor both mean "the new teacher". Putting the adjective first stresses it and sounds more written: you meet it in the news, in books and in speeches more than in the street. With mare the meaning changes as well: marele scriitor is the great, famous writer; scriitorul mare is the big or tall one. A few adjectives nearly always come first, so you will always see them with the article: fostul (the former), ultimul (the last).