Latin (in wide use in English) for nonsensical response? [duplicate]

There is a Latin term or phrase (in wide use in English, esp academic discourse) that one uses in situations like the following:

1. one makes a statement or asks a question

2. one's interlocutor makes a response that is simply nonsensical: either per se, or which does not relate to the statement or question

The Latin (IIRC--could be Greek) term or phrase is adjectival, in that it describes (and implicitly denigrates) the response. I suspect it begins with 's' (but ICBW). I know I have used this in the past, but I simply cannot recall--please help!

Solution 1:

Could be a non-sequitur. Per MW:

a statement (as a response) that does not follow logically from or is not clearly related to anything previously said

This is from Latin, and literally it means: "it does not follow."