If you mean 'let it go' as in, stop talking/worrying about it, then you could use "Fág é" ('Fawg ay'), which means 'leave it.'
lig sé a - literal translation
lig sé amháin- leave it alone/leave it
In Irish it's "Siúil leat"
lets go for lunch
lets go private
You say "Lets go!" in Maasai language of the African origin as "Maape!".
allons-y France allons-y
Taitníonn tú go mór liom. (Irish)Scots Gaelic (?)
"ChodΕΊmy" is a common way to say "let's go" in Polish.
"Ας πάει"
namuk pokam
In Irish it's "Saints abú"
In Irish it's: cinnte / go cinnte
dul níos tapúla
Darach go deo