‘但凡’ is a conjunction meaning ‘as long as’ or ‘if ever’, used to introduce a minimal or hypothetical condition — often implying that the condition is easy to meet or almost always true. It combines 但 (dàn), which historically means ‘but’ or ‘only’, and 凡 (fán), meaning ‘all’, ‘every’, or ‘any’. Together, they form an emphatic conditional expression: literally ‘only all’ → ‘in any case where…’. It’s more formal and literary than everyday spoken alternatives like 如果 or 只要, but remains common in written Chinese and formal speech.

This word frequently appears in advice, warnings, generalizations, or rhetorical statements — for example, when stressing inevitability or universality of an outcome given even the slightest condition. It carries a slightly elevated or solemn tone and is rarely used in casual conversation among young native speakers, though it’s widely understood and taught in textbooks for intermediate learners.