As nouns the difference between fulness and saturity
is that fulness
is being full; completeness while saturity
is (obsolete) the state of being satiated; fulness, repletion.
Being full; completeness.
The degree to which a space is full.
(fig. ) The degree to which fate has become known.
(bodybuilding): A measure of the degree to which a muscle has increased in size parallel to the axis of its contraction. A full muscle fills more of the space along the part of the body where it is connected.
* in the fulness of time
(obsolete) The state of being satiated; fulness, repletion.
*OED 2nd edition 1989