In children's apps the word has been stretched a long way. “Ad-free” can mean no banners but a video to earn coins; or ads only in the free tier; or house ads, which are still ads. So, specifically:
LingoSprout shows no advertising anywhere, in any tier, to anyone. There is no rewarded video, no interstitial, no banner, no sponsored content and no promotion of other apps. The free version is not an ad-supported version — it is the same app with fewer word categories.
