彼の言っていることは全部でたらめだ。
Everything he's saying is nonsense.
No one believes such a ridiculous story.
He's always talking nonsense.
The newspaper had a completely baseless story written in it.
He picked the numbers completely at random.
He's living a completely disorganized life.
でたらめ describes something nonsensical or careless in general, whereas 根も葉もない specifically emphasizes that a rumor or claim has no factual basis at all.
でたらめ carries a negative sense of nonsense or unreliability, whereas ランダム is neutral and simply means lacking a pattern.
でたらめ describes nonsensical or random falsehoods with no basis, while 作り話 implies a coherent, deliberately constructed story.
でたらめ emphasizes randomness or made-up nonsense, whereas 滅茶苦茶 stresses chaos, disorder, or excess.
でたらめ suggests something random, nonsensical, or unreliable, whereas 不規則 simply means lacking a fixed rhythm or rule.
でたらめ describes nonsense or something made up carelessly, whereas 嘘 specifically means a false statement, often but not always deliberate.
でたらめ emphasizes randomness or irresponsibility in what's said or done, whereas 意味不明 just says the meaning can't be grasped.
でたらめ describes something random, nonsensical, or unreliable, whereas インチキ specifically implies intentional cheating or fakery.