Watchdog rhymes with:
bulldog, gundog, hotdog, lapdog, underdog, analog, analogue, bulldog, bullfrog, catalogue, dialogue, eggnog, epilogue, gundog, hotdog, lapdog, leapfrog, metagogue, monologue, sandhog, synagogue, travelogue, underdog
Watchdog sounds like:
watchdogs, wedgewood's, whitesides, widgets, woitschatzke, woodsheds, woodstock