Antonym of "smalltalk"?

According to wikipedia, smalltalk is an informal type of discourse that does not cover any functional topics of conversation or any transactions that need to be addressed. For example:

• William: Morning, Paul.
• Paul: Oh, morning, William, how are you?
• William: Fine, thanks. Have a good weekend?
• Paul: Yes, thanks. Catch you later.
• William: OK, see you.

I haven't found a word to describe the opposite: an informal type of discourse that DOES cover a functional topic of conversation or a transaction that need to be addressed.

Could we say "deep talk"? Maybe just "non-smalltalk" is the best option?

Solution 1:

I would call it serious conversation.

Solution 2:

I would say either discussion or discourse, or even intercourse, although intercourse doesn't necessarily imply that the talk actually achieved a communication objective.

Solution 3:

"talk" would be the best option.

If you say to someone "We need to have a talk" or "Can we have a talk?", it obviously implies a meaningful one.

Consider also meaty and "substantial" talk (or discussion, conversation).

Solution 4:

substantive suhb-stuh n-tiv/ adjective

having practical importance, value, or effect.

A substantive conversation as opposed to "small talk"

small talk smôl ˌtôk/ noun

polite conversation about unimportant or uncontroversial matters, especially as engaged in on social occasions.

Both a substantive conversation and small talk are also in contrast to a rhetorical argument.

rhetorical rəˈtôrək(ə)l/ adjective

expressed in terms intended to persuade or impress.

To best choose which term to use, consider the content, intention and setting.