. . . you may be basing that confusion on a false perception:
"the only difference is the ending, making it feminine"
In
European languages, yes, it's common to feminise a name by sticking a vowel sound or two on the end of it. But that doesn't necessarily hold for other language groups. Both
Manisha and
Manish have meanings that relate to the mind/thought, so they are clearly related linguistically, but they each take a different slant on it.
The reason for that could be that (as a purely speculative
made-up example as I don't know the language):
Manisha could be composed of two words, 'man' and 'isha', while
Manish would be composed also with the word 'man', but with the word 'ish' instead, which would be related to 'isha' but would not be the same word and would have slightly different meaning.
To give a real example of this, take the English words "Blacksmith" and "Blacksmithy". They both include the word "black", but one contains "smith" and the other contains "smithy". Therefore the first indicates the person doing the job (smith) and the other refers to the place in which the person does that job (smithy). Very similar, only separated by the vowel on the end, but having different meanings.
Make sense?
♦ Chrisell ♦
All we have to decide is what to do with the time that is given us. - J.R.R. Tolkien.