Legitimate means properly lawful and fair, or genuinely valid. A legitimate business, a legitimate question, legitimate concerns.
It covers two related ideas: legal, as in a legitimate claim, and reasonable, as in a legitimate worry — the second is much the commoner in argument. As a verb, stressed differently, to legitimate something is to make it lawful, though legitimise is the usual form. Note legitimacy, which in politics means the accepted right to govern; and that legitimate once chiefly meant born to married parents, a sense now nearly gone.
1adjectivelegitimateProperly lawful.
“It is a legitimate business and it is audited every year.”
2adjectivereasonableReasonable and defensible.
“That is a legitimate question and nobody answered it.”
legitimate is a quality of validity.
Latin legitimus means lawful, from lex, law — the same root as legal, legislate and privilege. English borrowed the legal word and then let it soften into an adjective for anything defensible.
Latin
lēgitimō — to make legal
Medieval Latin
lēgitimātus
Middle English
legitimat
English, today
legitimate
From Middle English legitimat, legytymat, from Medieval Latin lēgitimātus, perfect passive participle of Latin lēgitimō (“to make legal”) (see -ate), from Latin lēgitimus (“lawful”), originally "fixed by law, in line with the law," from Latin lēx (“law”). Originally "lawfully begotten". The noun was derived from the adjective within English or earlier by substantivization (see -ate), the verb from the adjective by conversion (see -ate).
Etymology from Wiktionary, CC BY-SA