rdza, rdzi, rdzu:
Walter Simon (Simon 1980: 132–133) has suggested that rdza “clay,” rdzi “to press, knead,” and rdzu “to give a deceptive appearances” are related and that their parallel in Latin fingo “to knead, mould, shape” and “to devise, contrive, invent, feign,” figulus “potter,” and fictilis “made of clay.”
In the meant time, the Pandora box has been opened. There seems to be a host of words that need to be considered in addition to our initial list of rdza, rdzi, and rdzu. Joy suggested rdzas “substance/stuff.” Now rdza in the sense of “clay” should be understood as a specific kind of “substance” that one can “knead” (rdzi) so as to “give the shape/form” of an “earthenware” (rdza ma). Possibly rdzus ma “counterfeit” (Jäschke 1881: s.v.) also spelt rdzun ma (Bod.rgya) and rdzun “a lie” must be derived from rdzu ba “to feign.” But then, as Dan asks, what about rdzi bo and rdzi ma? Indeed rdzi bo (and hence all related compounds such as lug rdzi and bu rdzi) may well be derived from rdzi ba, not in the sense of “to knead,” “to tread,” “to crush, to oppress, to distress” (Jäschke 1881: s.v.) but rather in the sense of “to rule/govern” and indirectly “to oversee.” Compare English “governess” and Tibetan bu rdzi “nanny or babysitter.” By the way also compare the above rdzi ba with bzi ba “to be agitated” (dkrugs pa) or “to be intoxicated.” As for rdzi ma, the jump from rdzi ba to rdzi ma seems simply too long and unnatural. Neither the meaning of rdzi “wind” in rdzi char, rdzi phyogs, and rdzi ’phrig) (brDa-dkrol, s.vv.) nor rdzi “odour/scent” in rdzi med, rdzi langs, and rdzi rig seems to be useful for explaining rdzi ma. I must try try something else. I wonder if rdzi ma is actually connected with expressions like zim zim (Bod.rgya), which is explained as the manner in which eyes blink, light rain drizzles, and light snow falls. Note that the Bod.rgya records zi ma as a vernacular version of rdzi ma. In all of these, I see two common attributes, namely, quick fluttering movements, and thin filament-like appearances. Could it be that eyelash (rdzi ma) is thus something that consists of thin filaments and flickers constantly. Frankly, this seems to be too wild a speculation. I shall revoke this speculation as soon as I find a better one.