Had not heard of the term myself but just googled "Swiftian" (as the author was Jonathan Swift) and yep this seems to exist. It fits and makes sense too.
truck
possibly, aunt
Possibly sacroiliac joint
Possibly the letters with no lines of symmetry.
OHIO possibly?
Unlike terms, possibly.
The word is possibly "muted."
This could be a "clast" or possibly a "stone".
Possibly you mean the letters agndaigu ('i' instead of 'y') as this would form the well-known Australian town of Gundagai.
No Christmas carols have the letters OIRCD. However, you're possibly referring to OIRDC which is the carol Once in Royal David's City.
It is possibly the vowels: A I E O and U
Possibly, it's never really discussed in the books.