This is the 70th most frequent Hungarian word.
teljes
Complete; full; entire.
In this sentence, 'teljes' is used as an adjective meaning 'complete' to describe the noun 'könyv' (book).
Ez egy teljes könyv.
This is a complete book.
Here, 'teljes' functions as an adjective meaning 'full' or 'whole,' modifying the noun 'figyelmemet' (my attention).
A teljes figyelmemet neked szentelem.
I dedicate my full attention to you.
In this case, 'teljes' is part of the adverbial expression 'teljes mértékben,' meaning 'completely,' used to qualify the verb 'egyetértek' (I agree).