If there is an inexhaustible supply of something, there is so much of it that it cannot all be used up. She has an inexhaustible supply of enthusiasm = endless. something that is inexhaustible exists in such large amounts that it can never be finished or used up
incapable of being entirely consumed or used up; "an inexhaustible supply of coal" that cannot be entirely consumed or used up; "an inexhaustible supply of coal
{s} cannot to be used up, cannot be consumed or spent; cannot be tired out, indefatigable, unfailing
Incapable of being exhausted, emptied, or used up; unfailing; not to be wasted or spent; as, inexhaustible stores of provisions; an inexhaustible stock of elegant words
incapable of being entirely consumed or used up; "an inexhaustible supply of coal"