Worthy means deserving respect or the thing in question. A worthy cause, worthy of note, a worthy opponent.
On its own it has gone slightly sour — calling a book worthy now suggests it is dull and good for you. Worthy of, though, is neutral and useful. Note worth beneath it, and the -y ending that turns a noun into an adjective.
1adjectiveworthyDeserving respect or the thing in question.
“Her brave actions are worthy of the highest praise.”
worthy is a quality of deserving.
Old English weorthig is worth plus the -y ending that makes adjectives.
Old English
*weorþiġ — worthy
Middle English
worthy
English, today
worthy
From Middle English worthy, wurthi, from Old English weorþiġ (“worthy”), equivalent to worth + -y. Cognate with Dutch waardig (“worthy”), Middle Low German werdig (“worthy”), German würdig (“worthy”), Swedish värdig (“worthy”), Icelandic verðugur (“worthy”).
Etymology from Wiktionary, CC BY-SA