fruitless effort; wasted effort; futility
Refers to effort that yields no result; often used in formal or written contexts. The gloss 'abortive scheme' is a narrower, less common nuance.
His efforts ended up being in vain.
Doing that would be nothing but wasted effort.
Years of research came to nothing.
I tried to persuade him, but it turned out to be futile.
Opposing it now is a pointless effort.
骨折り損 is a vivid, colloquial phrase for wasted effort (literally 'broken-bone loss'), whereas 徒労 is more formal and abstract.
空回り describes effort that spins without traction or progress, while 徒労 emphasizes that the effort ultimately produced no result at all.
徒労 is a noun describing effort that turns out to be wasted, while 無益 is the na-adjective describing something as unbeneficial or futile.
徒労 focuses on the wasted effort itself, while 水泡 (in 水泡に帰する) focuses on that effort or plan vanishing into nothing like a bubble.
成果 is the positive result or fruit of one's effort, the opposite of 徒労, which is effort that yields nothing.
Compound of 徒 (futile, vain) and 労 (labor, effort). The exact historical derivation is uncertain, but the meaning is transparent from the kanji components.