self-deprecation

etymology of deprecation:

deprecation
1490 (deprecative), from M.Fr. deprécation, from L. deprecationem, from deprecari "plead in excuse, avert by prayer," from de- "away" + precari "pray." Sense of "show disapproval" is first attested 1612.

... to pray away ...
... to avert by means of prayer ...

with relation to "self," what could this mean? ...