In

As defined by A Concise Dictionary of Old Icelandic (Geir Zoëga):

in

temp. adv., pleonast. before a compar., hélt-a in lengr rúmi, he kept not his place longer, he ran away; mann in harðara = harðara mann, a hardier man; nema þú in snotrari sér, unless thou art wiser; né in heldr, neither; né hests in heldr, nor of his horse either; eigi in heldr ætla ek þat, neither do I think that.

Possible runic inscription in Younger Futhark:ᛁᚾ