Recently, an affective turn in the social sciences has re-appraised the role of affects and emotions in politics. However, the meaning, expressions and political impacts of individual affects still remain largely unexplored. In this paper, we propose to empirically document the affect of indignation through a qualitative study of the Belgian extenstion of the Yellow Vest (BYV) movement. Drawing on data collected by means of focus groups and participant observations at protest actions, we attempt to define what indignation means, and what its potential political effects might be. We approach theses questions through the notions of “political signifier” and “catalyst” to understand the collective expressions of indignation, and of “resource” to explore its individualities and anchoring in personal trajectories of engagement. This working paper is a starting point on two fronts: it lays the first steps towards the development of “indignation” as conceptual and interpretative framework, and it provides a first layer of descriptive analysis of the many faces of indignation that co-exist within the BYV movement.