Anatomy . the spinal column; spine.

strength of character; resolution.

something resembling a backbone in appearance, position, or function.

Bookbinding . a back or bound edge of a book; spine.

Nautical . a rope running along the middle of an awning, as a reinforcement and as an object to which a supporting bridle or crowfoot may be attached.

Naval Architecture . the central fore-and-aft assembly of the keel and keelson, giving longitudinal strength to the bottom of a vessel.

noun

ineptness , powerlessness , spinelessness , weakness

noun

courage , determination , firmness , fortitude , grit , guts , hardihood , heart , intestinal fortitude * , mettle , moral fiber , nerve , pluck , resolution , resolve , spunk , stamina , steadfastness , tenacity , toughness , will , willpower , base , basis , foundation , spine , support , vertebrae , vertebral column , character , chine , mainstay , rachis , spinal column , spirit