A fastening element operable for securing to a shank of a bolt-like element, the fastening element comprising an engaging part and a head part. The engaging part, comprises a longitudinally extending bush and an engaging body that projects radially inward. The bush and the engaging body partially define a receptacle in which the shank of the bolt-like element can be received. The head part is arranged above the engaging part and comprises a main body and a supporting portion. The head part is movably engaged with the engaging part by a bayonet catch and can be moved between a free position and a locked position, and, when in the locked position, the supporting portion covers the engaging body and blocks the engaging body from moving in translation along the longitudinal axis.