Possible Clues:

• That's it! More in the water, perhaps
• It sounds comparatively amphibious
• It sounds more amphibious, perhaps
• Neither m nor f
• A gender
• Pronoun category
• Of noun, neither masculine nor feminine
• It's it that sounds like more of an amphibian, perhaps
• That's it - more amphibious, perhaps
• The thing is comparatively amphibious, it seems