1 a valid criticism
well founded, sound, well grounded, reasonable, rational, logical, justifiable, defensible, defendable, supportable, sustainable, maintainable, workable, arguable, able to hold water, plausible, telling, viable, bona fide; cogent, effective, powerful, convincing, credible, believable, substantial, forceful, strong, weighty, authoritative, reliable
Choose the right word
valid, sound, cogent
When applied to reasoning, valid indicates that something has the power to convince: a valid argument contains no errors of logic, and a valid conclusion follows logically from the argument in its favour. Valid can also refer to things that are legally binding or acceptable ( a valid passport is essential when you travel abroad).Sound can have the sense ‘solid’ or ‘dependable’. An argument or position that is sound is secure against objections because it is based on good evidence and accurate reasoning ( scientifically sound papers).Cogent denotes arguments that are clear, logical, and likely to influence the opinions of others ( it was Williams who marshalled the evidence, and he did so in cogent terms | an impassioned and cogent plea for judicial reform).