However, jheem, it functions as an adjective here.

Sorry, AnnaStrophic, but I have to disagree with you here. It's a noun modifying another noun. Consider the following.

1a. the red book
1b. the very red book
1c. the book is red
1d. the book which/that is red

2a, the diaspora Moroccans
2b. *the very diaspora Moroccans
2c. *the Moroccans are disapora
2d. *the Moroccans who are diaspora

Diaspora here does not act as an adjective nor is it an adjective, but it is a noun.