Is it ensure, insure, or assure?
1828, American English, from cup (n.) + cake (n.), probably from the cups they are baked in, but possibly from the small measures of ingredients used to make them. Meaning "attractive young woman" is recorded from 1930s, American English.
Weak; soft; wimpish: On cupcake opponents: It doesn't matter who you play. When you cross those black lines you should come out and play hard (1990s+)