"Is there a wolf in the field?"
Translation:An bhfuil mac tíre sa ghort?
It’s spelled mactíre in the EID entry for “wolf”, but the FGB equates mactíre to mac tíre (one has to refer to mac in the FGB to find the English translation), and Dinneen’s dictionary has it only as mac tíre. The NEID also only gives mac tíre for “wolf”. Perhaps mactíre was an early spelling reform that was subsequently reverted?
How about faoil? Is it old-fashioned or could it be used here? Because they don't accept it as correct answer…
The FGB notes that faol is a literary term for wolf. Faoil is the genitive form. Cú allta is also translated as "wolf".
Bearing in mind that it's been a few centuries since wolves were common in Ireland, they mainly exist in stories and legend, and mac tíre is the commonly used term in that context. If you were writing an article about the re-introduction of the gray wolf to Yellowstone, you might write about an faolchú liath, but if you're writing about Little Red Riding Hood, then mac tíre is more appropriate.