Meaning

adjective extraordinarily good or great ; used especially as intensifiers

adverb (used as an intensifier) extremely well

originFrom Middle English wondrous, alteration after the suffix -ous of Middle English wonders (“wondrous, wonderful”, adjective), from Old English wundres (“of wonder”), genitive singular of wundor (“wonder, miracle”), from Proto-Germanic *wundrą (“wonder”). Compare Dutch wonder, German Wunder.

Etymology from Wiktionary, CC BY-SA 3.0