grudgingly
2 occurrences across the corpus
King James Version
2 Corinthians 9:7
Every man according as he purposeth in his heart, so let him give; not grudgingly, or of necessity: for God loveth a cheerful giver.
OT Pseudepigrapha
Psalms of Solomon 5:15
Man's goodness is (bestowed) grudgingly and . . .; And if he repeat (it) without murmuring, even that is marvelous.