I'm refering to the movie Kill Bill.

I was wondering if Kill Bill and all those girls Black Mamba had to fight were Samurai or just regulars that know how to fight with swords.

No. Ronin at best, skilled assassins at worst. No samurai ethic, no embracing the concept of bushido, no giri/ gimu.

What is giri gimu?
I thought the movie mentioned she was a samurai.

She could be a samurai, but then who is her master, and why doesn't she live in feudal Japan? She's an assassin.

I don't remember anything about samurai in that movie, though she was called a warrior at least twice.

Giri/ gimu is the concept of honour, respect and obedience owed to those "above" you and concern, respect and fulfilment of obligations (societal duty) to those "below" you.
Killing people for money with allegiance paid only to your boss is hardly a samurai concept.

Besides, Samurai were illegalized in the late 1800s during the Meiji administration, who saw the Samurai as a part of the old ways, of feudalism and disunity.

OK so the movie either:
A - Specifically said she was a Samurai.
B - Specifically said she was not a Samurai.
C - Did not specify whether or not she was a Samurai.

you should watch it and find out.