In this paper our goal is to define a renormalised dissipative measure-valued (rDMV) solution of compressible Navier-Stokes system for fluids with nonmonotone pressure-density relation. We prove existence of rDMV solutions and establish a suitable relative energy inequality. Moreover we obtain the Weak (Measure-valued)-Strong uniqueness property of this rDMV solution with the help of relative energy inequality.• Pressure Law: In an isentropic setting, the pressure p and the density ̺ of the fluid are interrelated by :(1.4) Remark 1.1. The Consideration of h in (1.4) has been motivated from isentropic equation of state given by h(̺) = a̺ γ with γ ≥ 1 and a > 0.• Here we consider no slip boundary condition for velocity i.e. u| {∂Ω×(0,T )}=0 .( 1.5) The compressible Navier-Stokes equations admit global-in-time weak solution(s) for general finite energy initial data and a large class of pressure-density constitutive relations. Considering q ≡ 0 in (1.4) and following the literatures of Antontsev et al.[1], Lions[15], Feireisl[8], Plotnikov et al.[18] and many others, we observe globalin-time weak solution for adiabatic exponent γ ≥ 1 for d = 1, 2 and γ > 3 2 for d = 3. Even for non-monotone pressure, Feireisl in [7] has proved a similar result and recent work by Bresch and Jabin [2] indicates that for p ∈ C 1 [0, ∞) ≥ 0, p(0) = 0, lim ̺→∞ p ′ (̺) ̺ γ−1 = a > 0 and γ ≥ 2 the system admits a weak solution. So it may seem unnecessary to develop the theory of measure valued solution that extends the class of generalised solutions but in the following discussion we will try to justify why we still choose to consider it.