The Collaborative International Dictionary
Conclavist \Con"cla`vist\, n. [Cf. F. conclaviste, It. conclavista.] One of the two ecclesiastics allowed to attend a cardinal in the conclave.
Wiktionary
n. The personal aide of a cardinal at a papal conclave.
Wikipedia
A conclavist was a personal aide of a cardinal present in a papal conclave. The term is sometimes used to refer to all present with a conclave, including the cardinal-electors, but is more properly applied only to the non-cardinals. Conclavists played an important historical role in the negotiations of papal elections and in the evolution of secrecy (or the lack thereof), writing many of the extant accounts of papal elections.
Three popes have been elected from former conclavists, including Pope Pius VI (a conclavist in the 1740 conclave). Other conclavists have later been elevated to the cardinalate, such as Pierre Guérin de Tencin (1721), Niccolò Coscia (1724), Christoph Anton Migazzi (1740), and Carlo Confalonieri (1922).
Pope Paul VI in effect eliminated the role of the historical conclavist by banning private aides and creating a common support staff.
Usage examples of "conclavist".
The messenger who brought the letter, however, got mildly drunk in Sanly Bowitts and expressed his own opinion of the affair: either the cardinals would all appoint conclavists and go home for the winter, leaving a hopeless deadlock, or would elect an ill old man who could be expected to die before settling any real problems.
While they were indeed looked upon with horror by the cardinals of the Society, there was hardly any conclavist who was not looked upon with horror by somebody.
There were cots enough for the cardinals, but their conclavists slept on the floor.