Appreciative means showing that you value something. A murmur, a nod, a letter written the next day.
It takes of: appreciative of the effort, appreciative of the help. The word describes the showing rather than the feeling, which is what separates it from grateful, since somebody can be grateful in silence but appreciative only visibly. An appreciative audience is one that responds warmly, and an appreciative glance is a compliment paid without words. The verb appreciate also means to rise in value, which is a quite separate financial sense.
1adjectiveappreciativeShowing that you recognise the value of something.
“There was an appreciative murmur from the back.”
Proto-Indo-European
*per-
Latin
appretiātus — appraised
Medieval Latin
appreciātus — valued or appraised
English
appreciate
English, today
appreciative
From appreciate + -ive. appreciate Originated 1645–55; from Medieval Latin appreciātus (“valued or appraised”), later variant of Latin appretiātus (“appraised”), the perfect passive participle of appretiō (see -ate), from a(d) + preti(um) + -ō. Cognate to French apprécier. Latin root also origin of English a doublet of appraise, which has various Romance cognates; see also precious.
Etymology from Wiktionary, CC BY-SA