There is one query from Mr. Rajagopalan Seshadri, making a statement
So, we put in short indeclinable as लिङ्ग-विभक्ति-वचन-शून्यानि अव्ययानि.
I would like to respond as follows –
Your statement लिङ्ग-विभक्ति-वचन-शून्यानि अव्ययानि is not a good conclusion. For example किम् is usually a pronoun. But in a sentence such as सः गच्छति किम् ? ‘Does he go ?’ it is an interrogative and hence an अव्ययम्.
The concept in English grammar speaking of Parts of Speech classifies words into eight classes. The concept of अव्ययम् challenges that. In Sanskrit अव्ययम् encompasses, as I mentioned in my first post, adverbs, conjunctions, exclamatory words, auxiliaries (such as न for negation), also gerunds and infinitives.
Another example of a word which does have लिङ्ग, विभक्ति, वचन but is an अव्ययम् is वेगेन. So अव्यय-s are those words in a sentence, which, in a sentence, do not have to conform and have the same formatting as of another word. In a sentence अश्वः वेगेन धावति the word वेगेन does have a formatting. But that formatting does not conform, does not have to conform to the formatting either of अश्वः or of धावति.
So अव्ययम् is a concept of ‘no mandate of conformity of formatting’ and not of having formatting or not. Of course there are many अव्यय-s, which do not have any formatting whatsoever, e.g. न. हे, भोः. Even किम् has a formatting नपुंसकलिङ्गम्, प्रथमा विभक्तिः, एकवचनम्. But in a sentence such as सः गच्छति किम् ? its formatting does not conform to the formatting of सः or of गच्छति.
Actually there is some discussion about उपसर्ग-विभक्ति-स्वर-प्रति-रूपकाश्च in the commentary on the सूत्रम् स्वरादिनिपातमव्ययम्. So, the post on this needs further detailing.
Words which do not have any formatting whatsoever and are used in sentences are अव्यय-s. But words having formatting can also be अव्यय-s. So important criterion for identifying अव्यय-s in a sentence is the ‘mandate of conformity or not with the formatting of another word(s)’.