To grow strong or stronger.
To make strong or stronger; to add strength to; to increase the strength of; to fortify.
To empower; to give moral strength to; to encourage; to enhearten.
To reinforce, to add to, to support (someone or something)
To substantiate; to corroborate (a belief, argument, etc.)
To augment; to improve; to intensify.
To make or become mentally tougher.