Reducer and Weight watcher

Reducer noun - A substance capable of bringing about the reduction of another substance as it itself is oxidized; used in photography to lessen the density of a negative or print by oxidizing some of the loose silver.

Weight watcher and reducer are semantically related. In some cases you can use "Weight watcher" instead a noun "Reducer".

Reducer and weight watcher are semantically related. You can use "Reducer" instead a noun phrase "Weight watcher".