1. You will have another cake.
(Does 'have' mean 'eat'?)
2. It's a lovely day.
(What does 'lovely' mean? What other similar expressions can we use instead of 'lovely'?)
1 - Yes, in that sentence "have" usually means "eat." It could also mean that you've bought or made the cake but haven't eaten it yet!
2 - http://www.answers.com/lovely
Other words you could use are "beautiful" and "gorgeous" and "splendid" and a few others that mean about the same thing.