meaningful

Meaningful describes something that has a purpose, that is important or that has value. (adjective)

When you have a conversation with someone that is about something substantive and more important than just idle chat, this is an example of a conversation that would be described as meaningful.
When someone gives you a present that has value and that you truly appreciate, this is an example of a meaningful gift.
When someone gives you a glance that communicates a message to you, this is an example of a meaningful glance.

See meaningful in Webster's New World College Dictionary