Readily, with willingness and preparedness. The adverbial form emphasizes not just being in a state of readiness but acting with willing eagerness. Used by Peter to describe the willing spirit of shepherds who serve God's flock without compulsion.
Hetoimos as adverb captures the spirit of willing service. Peter tells elders to shepherd 'not reluctantly, but readily' (1 Peter 5:2 variant). Paul says he is readily prepared to visit (2 Corinthians 12:14). Christian service that is grudging or forced misses the mark — God loves a cheerful giver, and hetoimos describes that cheerful readiness in action.