It means that something is 'assumed', rather than directly stated. So - If, in the evening, you asked a woman to breakfast at your house, the 'explicit' invitation is to have breakfast. But you are implying that you are inviting her to stay the night beforehand. Or - If I told you that 'you need a shower' - I am saying that you need a shower, but I am implying that you smell, and that is why you need a shower.

When something is "implied" it means that the meaning of this is already explicit (or implicit, or implied :)) on the stating.