I agree with David on the first part. It could be "paññā" (wisdom) as well as "pañña" (wise or endowed with knowledge). The second part could be a form of "vuḍḍha".
vuḍḍha = old (fig. venerable)
Since the second part "vuḍḍho" seems to be the adjective I think the first part may be a noun, thus "Paññāvuḍḍho" could be translated as "vernerable wisdom" or something like that.
However my Pali is not good... just my 2 cents
best wishes, acinteyyo
Pubbe cāhaṃ bhikkhave, etarahi ca dukkhañceva paññāpemi, dukkhassa ca nirodhaṃ. (M.22)
Api cāhaṃ, āvuso, imasmiṃyeva byāmamatte kaḷevare, sasaññimhi samanake lokañca paññāpemi lokasamudayañca lokanirodhañca lokanirodhagāminiñca paṭipadan. (AN4.45)