How is רעב pronounced?
In other exercise:
ואני לא רעב ... = I (male) am hungry [pronounced reev]
הילד רעב ... = The boy is hungry [pronounced raev]
both should be the same. "Raev" :)
I have already looked for it in Forvo.com, and it agrees, It is "raev".
Why can't it mean "The hungry boy"?
The adjective would then take on a definite article, so it would be הילד הרעב
Is this hungry = רעב related to the adjective bad = רע ?
No. Most words in Hebrew have three letter roots. In this case, the root of רעב is resh-ayin-vet and the root of רע is resh-vav-ayin - vav is a weak root letter so it can drop.
The root of רע is actually ר.ע.ע. resh-ayin-ayin