。
The poor man was begging.
Literal
Poor-person [subject-が] beggar [object-を] doing [progressive-ていた].
貧困者 ('poor person, impoverished person') is a formal compound. 乞食 (こじき, 'beggar') is a sensitive word — it refers to someone begging for alms, and in modern Japanese can be considered derogatory or outdated; modern equivalents include ホームレス (homeless) or 物乞い (more neutral 'beggar'). 乞食をする means 'to beg.' The sentence uses straight-forward description typical of older narrative prose.