The word "indefinable" refers to something that cannot be clearly defined or described. The antonyms of this word are "definable," "clear," "certain," "obvious," and "distinct." Something that is definable can be easily explained, while something that is clear can be easily understood. If something is certain, it is free from doubt or hesitation. Obvious means something is clear and easily noticeable or understandable. Finally, something distinct is unique or different from other things, making it easy to differentiate from them. By having a good understanding of these antonyms, you can better describe and understand the concept of indefinable things.