noun
plural saps
[noncount] :a watery juice inside a plant that carries the plant's food
[count] chiefly US informal :a person who is easily tricked or cheated
verb
saps; sapped; sapping
[+ obj] to use up the supply of (something, such as a person's courage, energy, strength, etc.)
to cause (someone) to lose courage, energy, strength, etc. - usually + of