Making Adverbs: -α and -ως

Most Greek adverbs are built straight off an adjective, and the everyday ending is -α: καλός → καλά (“well”), γρήγορος → γρήγορα (“quickly”), εύκολος → εύκολα (“easily”), προσεκτικός → προσεκτικά (“carefully”). The shape is not new to you - the adverb is spelled exactly like the NEUTER PLURAL of that same adjective, tonos and all, so if you can decline the adjective you can already write its adverb. The second ending, -ως, is the formal / learned one, and it is the REGULAR ending for the -ής/-ής/-ές adjectives you just met: ακριβής → ακριβώς (“exactly”), ασφαλής → ασφαλώς (“certainly”), συνήθης → συνήθως (“usually”). A -ώς adverb is always stressed on that last syllable. A few adjectives make BOTH forms with DIFFERENT meanings - απλά (“plainly, in a simple way”) beside απλώς (“merely, just”), άμεσα (“directly”) beside αμέσως (“at once”) - so the two endings are not interchangeable. And not every adverb comes from an adjective at all: εδώ, τώρα, πάντα, ξανά, μαζί are adverbs in their own right and have no adjective behind them.