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Indeed
In reality; in truth; in fact; verily; truly; -- used in a variety of sense. Esp.: (a) Denoting emphasis; as, indeed it is so. (b) Denoting concession or admission; as, indeed, you are right. (c) Denoting surprise; as, indeed, is it you? Its meaning is not intrinsic or fixed, but depends largely on the form of expression which it accompanies.
In that manner or degree; as, indicated (in any way), or as implied, or as supposed to be known.
oewn 202368% interchangeable
Open English WordNet places these words in at least one shared synset. They share a lexicalised sense, but context, register and collocation should still be checked before substitution.