Definition of "retiring"

My uncle, as I can remember, was retiring in his disposition, scarcely ever visiting any one and not more frequently receiving any visitors.

1861, E. J. Guerin, Mountain Charley, page 10

Lester was in the thick of social and commercial affairs; he walked in paths to which Jennie's retiring soul had never aspired.

1911, Theodore Dreiser, chapter LX, in Jennie Gerhardt‎

One day of those his retirings [sic], giving out that he was sick, his father Antigonus came on the sudden to visit him, and met a fair dainty youth coming out of his chamber.

1625, Francis [Bacon], Apophthegmes New and Old. […], London: […] Hanna Barret, and Richard Whittaker, […]