Discuss and learn French: French vocabulary, French grammar, French culture etc.
I think the one work exclamation "entendu" could work for you. It just means "understood".
"Absolument !" ?
An idiomatic way of saying this would be "Je suis tout à fait d'accord avec toi" or, in response to a proposition, simply "Tout à fait!". Neither is overly colloquial (nor overly formal), though.
"On est d'accord" would be ok as well, it is less formal than "Je suis tout à fait d'accord avec toi" while meaning the same thing.
C'est sur/C'est clair: "it's obvious" or something like "yeah totally", "clair" is much less formal than "sur", both are often used
Thanks to everyone for your replies-this is helpful!