> The books often give adjectives at the end of these compounds, as I
>showed in > my last post.

Suppose I then propose that the subject of a Pali sentence can also
be an adjective.

Viiro gacchati.

Viiro is an adjective meaning 'heroic'. Hence the above means: Heroic goes.

Does that sound a bit absurd? Of course. The solution is simply that
adjectives very often function as nouns in Skt/Pali. Viiro there just
means 'hero': the hero goes.

Similarly, 'dutiyo' in the example you brought really can be read
'companion'. To repeat my previous counterexample, dutiyo there was
no more functioning as an adjective, than does 'second' in: The
prince arrived at the duelling place at dawn with his trusted friend
as his second. The word has acquired further semantic content, far
beyond just the idea of the ordinal numeral in both cases. With pali
'dutiyo' it has acquired the idea of being something that
accompanies, with eng. 'second' it's similar, but it is further
restricted to duelling.

'Sama' in asama (lacking an equal) really does mean here 'an equal'
i.e. is functioning as a noun. By way of comparison, there is an
another use of 'asama' meaning 'uneven', as in uneven ground, which
is bad for chariots. This latter is based on the adjectival use of
sama.

Another of your examples was farther off: mattaa (f) really does mean
'a measure'. The so-called adjective -matta (ifc) is a form that has
resulted precisely from making bahubbiihis from the noun mattaa.

/Rett