To weaken or deprive of strength, sinews, or vigor; to make feeble or powerless.
From dis- (opposite) + sinew. Sinew originally meant the tendon connecting muscle to bone, but metaphorically came to mean strength or vigor. Adding dis- reverses this, meaning to strip away strength.
This is a rare word that beautifully uses 'sinew' (the tough tissue that makes you strong) as a metaphor—so 'dissinew' means literally robbing someone of their strength and toughness!
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