[viciousvoxel]

Not parent but yes; related meanings (e.g. hate/torture, ask/know) and typically same part of speech (e.g. both verbs or both adjectives), and the lines having similar (but here reversed) sentence structure (another commenter posted the wiki link to Chiasmus which goes into more detail.

The structure we see here is x0 and y0, ...z0 / z1... y1 and x1.

[academia_hack]

Exactly this! It gets even cooler in this example too because the meter for "Odi et amo" elided to "Od'et amo" directly parallels the scansion for "excrucior" (long syllable, short syllable, short syllable, long syllable). So the two concepts that start and end the poem (love+hate, and torture) are also linked by how they are pronounced. Incidentally, that linkage is also the message of the poem itself.

These two lines are basically just Catulus' being a complete show-off. And IMO, some of Ovid's work makes Catulus look like a bit of an amateur by comparison.

Classical latin poetry is like 10% being able to write down clever ideas and 90% showing off your grasp of grammar and vocabulary such that you can pose and solve incredibly difficult linguistic puzzles. I think Sanskrit is pretty similar in this respect too.

[viciousvoxel]

Completely agree. Catulus was sort of a talented incel-type imho. I remember his work being way more fun to read and translate but Ovid was obviously more brilliant and...poetic.

[Rietty]

Do you have an example of Ovid's that make Catulus look like an amateur?