Recently, a measure of uncertainty termed by negative cumulative extropy (NCEX) is proposed
by Tahmasebi and Toomaj (2022). It is a flexible extension of extropy measure which was proposed by Lad,
Sanfilippo, and Agro (2015). To measure the uncertainty of uncertain variables, in this article, we propose
the concept of NCEX through uncertainty distributions. Some properties of NCEX are derived, and some
practical examples of uncertain variables are given. Several basic theorems are proposed. A formula of cross -extropy
is defined via inverse uncertainty distributions. We also delve into a pattern recognition problem to
highlight the importance of cross-extropy. Finally, applications to portfolio selection and signal processing are
presented.