Catch-as-catch-can essentially means haphazard, ad-hoc or random actions. Therefore, antonyms could include words such as orderly, systematic, pre-planned or deliberate. Words such as methodical, calculated, controlled or measured may also be appropriate antonyms. Catch-as-catch-can can also suggest an improvised, free-flowing approach, so antonyms might include words like structured, formal, tight or regimented. Alternatively, if catch-as-catch-can suggests a chaotic, disorganised approach, antonyms could include disciplined, focused, efficient or well-organised. Catch-as-catch-can can also suggest an unprepared, reactive approach, so antonyms might include prepared, proactive, planned or thoughtful. The specific antonym will depend on the context in which the term is being used.