Middle English word blissien comes from Proto-Germanic *blīþisjōną (To be good, be kind, be joyful.)

Detailed word origin of blissien

Dictionary entry	Language	Definition
*blīþisjōną	Proto-Germanic (gem-pro)	To be good, be kind, be joyful.
blissian	Old English (ang)	(intransitive) to rejoice; be glad. (transitive) to gladden; make happy; cause (someone) to rejoice; delight.
blissien	Middle English (enm)

Words with the same origin as blissien