i've been searching and i found some old posts here, one about Neysha and one about Naysha. I guess the Neysha post was also yours, because it was only a month ago. In that post the person said she was told it was of Turkish origin, but this is highly unlikely. What i did find were two websites both saying it was of Greek origin and it means 'pure'. I checked an online dictionary and found that pure in Greek is
agnes or
akeiaros . The first one is interesting because
Agnes is an existing firstname and also because the post of Naysha got a reaction saying Naysha was probably a pet form of
Agnes. With this result this seems true. Neysha is thus Greek and means 'pure'. See the hyperlink of
Agnes for more information.