thank⋅ful   /ˈθæŋkfəl/ Show Spelled Pronunciation [thangk-fuhl] Show IPA
–adjective feeling or expressing gratitude; appreciative.

Origin:
bef. 900; ME; OE thancful. See thank, -ful

Related forms:
thank⋅ful⋅ly, adverb
thank⋅ful⋅ness, noun

Synonyms:
beholden, obliged. See grateful. ( Edited by plmiller )  

http://www.bethankful.com/