The antonyms for "is derelict" can be interpreted in different ways depending on the context of the phrase. If we are referring to a place or a property, some antonyms could be well-maintained, operational, clean, or organized. In a more abstract sense, antonyms for "is derelict" could be responsible, diligent, reliable, or accountable. On a personal level, antonyms for "is derelict" could be productive, ambitious, motivated, or proactive. In any case, the opposite of "is derelict" encompasses a range of qualities that refer to an active, thriving, and functional situation, as opposed to a state of neglect, abandonment, or failure.