充盈 is a formal or literary word with both verb and adjective uses. As a verb it means 'to fill (a space) with something intangible or abundant', often followed by 着 and a noun like 笑容 (smile) or 力量 (strength). As a predicate adjective it describes a state of being full and rich — used for life, time, or resources. The adjective sense is similar to 丰富 but less colloquial.