Some fire alarms are not false! (4)

I believe the answer is:

real

I'm a little stuck... Click here to teach me more about this clue!

'not false' is the definition.
I can't judge whether this defines the answer.

'some fire alarms are' is the wordplay.
'some' indicates the answer is hidden within the clue (some parts of the word are used).
'REAL' can be found hidden inside 'fire alarms are'.

Can you help me to learn more?

(Other definitions for real that I've seen before include "Genuine, not imitation" , "Not imaginary, genuine" , "Actual, not illusory" , "serious" , "Actual; Brazilian currency" .)

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.