Lexember 8th: ‘to blink; to cause to blink’

blinkna

/ˈbliŋk.nɑ/ v.st.3 intr. to blink, to flash, to flicker.

From Middle Valthungian blinkn, from Griutungi blinkan, cf. Gothic *bligkan, from ProtoGermanic blenkaną.

https://linguifex.com/wiki/Contionary:blinkna

blenčin

/ˈble̞n.ʧin/ v.wk.1ija trns. to blink, to flash, to flicker.

From Middle Valthungian blenkšjen, from Old Valthungian blenkjan, from Griutungi blankjan, cf. Gothic *blagkjan, from ProtoGermanic *blankijaną.

https://linguifex.com/wiki/Contionary:blenčin

The main difference between these two terms is that the first is intransitive, while the second is transitive (or, more specifically, causative). E.g.:

blinkna: Þ·ōgana þis ǧužis blunkun. 

‘The creature’s eyes blinked.’

blenčin: Þat ǧus blankiða is ǭgana. 

‘The creature blinked its eyes.’