Alter

„Alter“ is a nominalization of the adjective „alt“ (old) and originally meant 'old friend / the old one'. In colloquial and youth language it is used as a value-neutral form of address for a (usually male) peer, much like English 'dude'. As a standalone exclamation „Alter!“ expresses emotional arousal – surprise, indignation or excitement – comparable to 'Man!' or 'Wow!'.