Pusillanimity

PUSILLANIM'ITY, noun [Latin pusillanimitas; pusillus, small, weak, and animus, courage.] Want of that firmness and strength of mind which constitutes courage or fortitude; weakness of spirit; cowardliness; that feebleness of mind which shrinks from trifling or imaginary dangers.

It is obvious to distinguish between an act of pusillanimity and an act of great modesty or humility.