もし

もし is used to introduce a hypothetical condition or circumstance that leads to a consequence. It marks the condition as tentative or uncertain. もしも is the emphatic variant and is often used to stress the conditional situation, sometimes in written or formal contexts. In daily speech, people also contract もし into もし, or omit it altogether when the context is clear. You can pair もし with なら or ても to form conditional sentences: もし + condition + なら + result (simple, future, or general). もし you use with ても to express ‘even if’ or ‘even though’ when the condition holds true but the result may still occur or not. Typical contexts include planning, hypothetical scenarios, warnings, or polite offers/proposals. Note that when expressing a wish or a hypothetical in the past, different constructions are used, but もし remains the marker for the hypothetical condition in present/future contexts.