Nouns ending in "-in": gender?

[Birgit Kellner]

Dear colleagues,

I was wondering whether there are any definite rules or established
practices concerning the gender of Sanskrit nouns ending in "-in".
All such words that I know have masculine gender (e.g. dharmin,
pratiyogin), and this seems also to be the case with most such words
lemmatized in Monier-Williams.

I have now some passages with -in-nouns in neuter gender and am
wondering whether this requires explanation. Is the gender of such nouns
a matter of habit and convention or one of grammatical rule?

One could imagine that these words originally derive from adjectives
which in turn are formed from nouns plus the in-suffix. If that is the
case, then the gender of the -in-noun might be derived from those nouns
with which the adjectives were most commonly used. By implication, the
-in-nouns would then be limited to specific contexts, where the
connection with the original noun (e.g. "dharma" in the case of
"dharmin") from which the adjective had been derived is still
semantically implicit. For instance, one might think that words like
"dharmin" and "pratiyogin" were originally adjectives used with a noun
like "artha" and retained a masculine gender because of this specific
usage.

By contrast, the occurrence of neuter nouns (like "virodhi") could be
explained through derivation from adjectives originally used with neuter
nouns (like "liGga"). But is it really plausible that the gender of
(some) nouns is a matter of such complicated derivations which tie nouns
to very specific contexts of usage? Or would the choice of neuter or
masculine in such cases be arbitrary, and the preference for masculine
simply be a matter of linguistic convention regardless of context of use?

Thanks in advance and best regards,

Birgit Kellner