largemouth black bass \ˈ ̷ ̷ˌ ̷ ̷-\noun alsolargemouthed black bassorlargemouth bassorlargemouthed bassorlargemouth : a wide-ranging and rather large black bass (Micropterus salmoides) chiefly of warm sluggish waters that is blackish green above and lighter or whitish below with the angle of the jaw falling behind the eye — compare smallmouth black bass