From The Collaborative International Dictionary of English v.0.48 [gcide]:
Rectitude \Rec"ti*tude\ (r?k"t?*t?d), n. [L. rectitudo, fr.
rectus right, straight: cf. F. rectitude. See Right.]
1. Straightness. [R.] --Johnson.
[1913 Webster]
2. Rightness of principle or practice; exact conformity to
truth, or to the rules prescribed for moral conduct,
either by divine or human laws; uprightness of mind;
uprightness; integrity; honesty; justice.
[1913 Webster]
3. Right judgment. [R.] --Sir G. C. Lewis.
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Syn: See Justice.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
rectitude
n 1: righteousness as a consequence of being honorable and
honest [syn: uprightness, rectitude]