be obliged, show gratitude, give thanks, acknowledge, show appreciation, be obligated to, be indebted to, bless, praise, bow down to, kiss, smile on, show courtesy, express one's obligation to; see also appreciate 1.
Antonyms neglect*, ignore, show indifference.
"thank." YourDictionary, n.d. Web. 17 August 2018. <http://thesaurus.yourdictionary.com/thank>.
thank. (n.d.). Retrieved August 17th, 2018, from http://thesaurus.yourdictionary.com/thank