In a downcast manner; sadly, dejectedly, or with a gloomy appearance or demeanor.
From 'downcast' (sad or directed downward) plus the adverb-forming suffix '-ly'; creates an adverb describing how an action is performed in a sad or downward manner.
This adverb is delightfully archaic—modern English just says 'sadly' or 'dejectedly,' but 'downcastly' has a literary, almost Victorian sadness to it! Poetry and novels from the 1800s are full of characters acting 'downcastly.'
Complete word intelligence in one call. Free tier — 50 lookups/day.