'går' is the present tense of 'gå' (to walk) and is also used to denote yesterday.
Not sure how I find my dictionary version. I've tested with Aspell 0.60.6.1.
It should probably be added to both 'no' and 'nb'
Extra references:
http://ordbok.uib.no/perl/ordbok.cgi?OPP=g%C3%A5r
http://ordbok.uib.no/perl/ordbok.cgi?OPP=g%C3%A5