No it is a synovial joint! There is some degree of free movement possible
multiaxial joint
A multiaxial joint is a type of synovial joint. The x-axial refers to how many planes of the movement the specific joint provides, so in the case of a multiaxial joint, that means it provides movement in many planes of movement (multiaxial usually refers to three, which can then also be stated as triaxial).
Ball-and-socket joint is an example of triaxial (or multiaxial) joint.
Sacroiliac joint
Ball-and-Socket Joints
The coxal bone is part of the hip joint.The longest bone in the body is the femur, thigh bone, which is a ball and socket joint with the hip joint or coxal bone.
On good authority the best answer to your question is - ball&socket
A ball-and-socket joint (multiaxial) connects the two bones.
I think the sacrum and coxal bone are joined at the sacroiliac joint.
the pubis or pibic bone
pubic symphasis