Game in Ohio, America, is exorbitant (7)
I believe the answer is:
Here is my best explanation:
'exorbitant' is the definition.
(I've seen this before)
'game in ohio america' is the wordplay.
'game' becomes 'ru' (rugby union).
'ohio' becomes 'o'.
'america' becomes 'us' (abbreviation for the United States).
'is' is the link.
(Other definitions for ruinous that I've seen before include "causing harm?", "Destructive; dilapidated", "far too expensive", "disastrous", "Disastrous, destructive", "Tumbledown - expensive", "Calamitous, crippling", "Exorbitant", "Catastrophic" and "Broken down".)