1) autumn trees
1a) trees such as they are at the close of autumn, dry, leafless and without fruit
1b) metaphorically of unfruitful, worthless men
Part of Speech: adjective
From a derivative of φθίνω phthinô (to wane; akin to the base of G5351) and G3703 (meaning late autumn) autumnal (as stripped of leaves): - whose fruit withereth.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root φθινοπωρινός; click on the second column to search for that grammatical form of the root φθινοπωρινός; click on the third column to search for that word and grammatical form; click on the total to search for the root φθινοπωρινός.