Abstract
This article focuses on issues related to the arbitrary and non-arbitrary nature of the
linguistic signs (monolexical and polylexical), the types and cases of linguistic motivation
and the criteria of lexical denomination. Several issues regarding to stable polylexical
units have been analysed from the motivational perspective: the genesis, existence and
use of linguistic signs, whose signifiers are expressed by stable polylexical units, two
types of semantic motivation (metaphorical motivation and symbol-based motivation) and
intertextuality as a specific type of motivation. In the course of its history, each figurative
expression has undergone its own evolution. In this context, the task of linguistic research
is not only to identify the productive motivational links that affect the functioning of
figurative expressions in actual discourse, but also to describe their true etymology.