Dear Mahipaliha,

> Regarding citta-gu: There is no problem as to the meaning, the
> constituent words or the type of samaasa.

Agreed.

> The only question is what
> is the root and what is the ending (suffix). It was customary to
> treat the root as cit- meaning to shine, appear bright, be
> visible/perceptible (also perceive etc.). citra/citta then means,
> (what is) bright, evident, noteworthy, whence a spot, spotted,
> brindled. If this is right (it is disputed, as often happens in the
> minefield of etymology), then -ra is the suffix. It is so treated by
> grammarians/linguists like Thumb. Whitney, Macdonell, Burrows. The
> latter in his work on the Sanskrit Language gives the following (and
> several other) words as having this suffix: ugra,vajra, udra,
> k.sudra, k.sipra, ajra, g.rdhra (whose Pali equivalents are ugga,
> vajira, udda, khudda(ka), khippa, ajira, gijjha. As far as I am
> concerned, this seems convincing and sufficient for understanding
> the word and its formation. I do not see any other important
> implications. It is much more difficult to connect the word to the
> root ci. to gather.

For investigating questions of etymology, I prefer to consult
traditional Pali and Sanskrit grammatical sources. I found a sutta in
the Moggallaanabyaakara.na that may support your suggested dervation
of citra (spotted) from the root 'cit' + the suffix 'ra'. I refer you
to Mogg VII 146 where the following is given for the derivation
of 'vicitra' : ". . . cita-sa~ncetane, vipubbo, vicintitabbanti
vicitra.m = naanaakaara.m, . . ." Mogg VII 143-146 describe the use
of the u.naadi suffix 'ra' (raka). Now I'm not sure if 146 can also
apply to 'citra'.

Here's a list of the roots 'cit':

From Aggavaa.msa's Dhaatumaalaa:
citii sa~n~naa.ne (to make a mark)
cinta (or citi) cintaaya.m
cita sa~ncetane

From Paa.nini's Dhaatupaa.tha
X.2 citi sm.rtyaam
X.144 cita sa.mcetane

For 'citra' derived from the root 'citr' (to paint, variegate)
and 'ci' (to heap, pile), I refer you to the two etymologies given in
Apte's Sanskrit dictionary: "[citr-bhaave ac; ci-.s.tran U.n 4.163]".

So now there are several possible etymologies for the word 'citra' to
consider.

Best wishes,
Jim