megilp

noun

1. (countable, uncountable)A mixture of linseed oil with turpentine or mastic varnish, used as a thickener for oil paints but later discredited as a source of cracking and yellowing.

   “He was in a hurry […] and instead of replicating the twenty or so layers of paint in the original he used megilp to give the impression of thickly applied paint.”