The headdress may indicate a hair style or cap.
The strongest impression is probably conveyed by the design of the head, i.e. the contrast between the detailed headdress and the total absence of facial features. The Venus of Willendorf does not look at us; she is self-contained, focusing inwards, possibly on a different reality. While the enigmatic lack of features contrasts with the individual, it gives her at the same time many different faces.