The phrase "in lying" can mean multiple things - from telling a lie to being in a state of horizontal repose. Depending on the context, one can use various synonyms to replace this phrase. For instance, instead of saying "I caught him in lying," one could say "I caught him fibbing," "I caught him fabricating," or "I caught him telling an untruth." Similarly, if one is referring to the state of being horizontal, they could use phrases like "reclining," "prostrate," or "lying down." The appropriate synonym would depend on the intended meaning of the phrase in context.