Here is a nice Avestan dictionary. http://www.avesta.org/avdict/avdict.htm
Avestan was one of the most important Arian languages. It's linguistic classification is still uncertain, because we still have not any good knowledge of most of old Iranian languages. Some say it is east Iranic some say west Iranic. But we know that it shares a significant philological isogolesses with poorly known language of Mede, than old Persian.
Here are some similar cognates of Avestan with modern Kurdish:
Avestan: modern Kurdish
Hamina: (Kurdish: Havin/hawin) (Kurdish spelling: Havîn/Hawîn) (English: summer)
Masya: (Kurdish: Masi) (Kurdish spelling: Masî) (English: fish)
Ve: (Kurdish: heve/êwe) (English: you)
Bareza: (Kurdish: Barz, barzai) (in Kurdish spelling: berz, berzayi), (English: height, mountain) (this word is also borrowed by muslims Kuran
)
Kanya:(Kurdish:Kani), (kurdish spelling: keni) (English: girl)
Azem: (Kurdish: az), (Kurdish spelling: ez) (old persian: adam) (I)
Maza: (Kurdish: mazn) (kurdish spelling: mezin) (English great, big)
Merekae: (Kurdish: Mirishk) (English: hen)
Pasu: (Kurdish: paz) (Kurdish spelling: pez) (English: sheep)
Zhnun: azhno (kurdish spelling: Ejno) (knee)
Ahma: (and in some cases ava) am, av, aw, (Kurdish spelling: em, ev, ew) (this, that, we) (This one is really really intersting because the word has several meanings and all its modern Kurdish equivalents are very similar and in some dialects the same )
Jan- :Jin ( plus ending of 'in') (Kurdish speling: Cinîn) (smite)
Peretum: (Kurdish: pird) (English: bridge)
And there are much more similar cognates....
Any comments?