Blade for a rotating bladed disk for an aircraft turbine engine, comprising at least one sealing lip extending axially projecting from a body of the blade and having two opposite circumferential end surfaces (64, 66), and one free axial end wherein the cross section is delimited internally and externally respectively by two concentric circle portions (68, 70), characterised in that the sealing lip has a connection cross section to the body of the blade which is delimited internally and externally respectively by an internal curved line and by an external curved line, each of the internal and external curved lines comprising: - a respective median portion, which is convex in a direction from a head of the blade to a root of the blade; - a respective first intermediate portion, which continuously extends from the respective median portion towards a first of the circumferential end surfaces of the sealing lip, and which is concave in the direction from the head of the blade to the root of the blade, whereby a respective first point of inflection separates the respective median portion from the respective first intermediate portion; - a respective second intermediate portion, which continuously extends from the respective median portion towards a second of the circumferential end surfaces of the sealing lip, and which is concave in the direction from the head of the blade to the root of the blade, whereby a respective second point of inflection separates the respective median portion from the respective second intermediate portion; and - a respective first end portion and a respective second end portion which respectively continuously extend from the respective first intermediate portion and the respective second intermediate portion, respectively to the first and to the second of the circumferential end surfaces (64, 66) of the sealing lip; each portion of the internal curved line being defined facing the corresponding portion of the external curved line, along the direction from the head of the blade to the root of the blade; and the cross section of the sealing lip being continuously non-constant from the connection cross section to the body of the blade to the free axial end of the sealing lip. - a respective median portion, which is convex in a direction from a head of the blade to a root of the blade; - a respective first intermediate portion, which continuously extends from the respective median portion towards a first of the circumferential end surfaces of the sealing lip, and which is concave in the direction from the head of the blade to the root of the blade, whereby a respective first point of inflection separates the respective median portion from the respective first intermediate portion; - a respective second intermediate portion, which continuously extends from the respective median portion towards a second of the circumferential end surfaces of the sealing lip, and which is concave in the direction from the head of the blade to the root of the blade, whereby a respective second point of inflection separates the respective median portion from the respective second intermediate portion; and - a respective first end portion and a respective second end portion which respectively continuously extend from the respective first intermediate portion and the respective second intermediate portion, respectively to the first and to the second of the circumferential end surfaces (64, 66) of the sealing lip; each portion of the internal curved line being defined facing the corresponding portion of the external curved line, along the direction from the head of the blade to the root of the blade; and the cross section of the sealing lip being continuously non-constant from the connection cross section to the body of the blade to the free axial end of the sealing lip.