I've just started reading Antimoon, and I came across their definition-word cards:
http://www.antimoon.com/how/usingsm-make...efword.htm

Does anyone have any experience with these? The only thing I found when searching was from '06, and I'm just wondering if there was any other thoughts about them, personal stories, etc.

It seems to me like once you amass a lot of vocab, it would be hard to differentiate between certain words

Reading their example cards, I can think of several words for each one so yeah, I would not recommend it.

Definition to word only really works when you are at a pretty basic level when you don't know many synonyms or near synonyms.