Functional traits are defined such as traits which affect individual fitness. I argue that the use of the term “functional trait” complicates the progress of the field because all traits are potentially linked to fitness. Obviating the potential link of all traits with fitness is related to dismissing (i) the integration of the phenotype, (ii) the spatio-temporal variation of environmental pressures and (iii) the genotype by environment interaction effect on the phenotype. These conceptual gaps could explain the weak predictive power of many functional ecology studies. I develop here some of the reasons why we should consider that all traits are related to fitness -advocating simultaneously for a change in terminology.