In our chemistry class, we learned that an acid is a molecular compound that release hydrogen ions when they are dissolved in water through a process called ionization. So are both Hydrogen Sulfide (g) and Hydrosulfuric Acid (aq) acids?
If you ask me - that's a nitpicky question that doesn't have a definitive answer.
Definition is not clear, as it doesn't specify how to treat potential acid - substance that WILL release H+ WHEN put in water, but it is not yet in water. You can argue that it is an acid (it will when) and that it is not an acid (it is not in water and it is not releasing H+). So it is semantics.
Could be my English fails me. Second opinion won't hurt.