La prima es una grande amiga.
Is the word "grande" the correct format, or is there a feminine form?
3 Answers
Gran/grande is one of a few adjectives in Spanish that don't change with gender.
So, in your example "mi prima es una gran amiga" is the correct way to go. This means she's a great friend.
In addition, adjectives which end with an "e" don't change with gender:
Examples: caliente (hot) "la comida está caliente"...valiente (brave) "mi amigo es muy valiente".
Hope it helps
La prima es una gran amiga.
The cousin is a great friend.
You can use 'gran' amiga. You made it feminine by using the feminine form of cousin, 'prima'. But gran is not like some adjectives that need a feminizing of the adjective.