The phrase "strike dead" refers to the act of killing someone instantly. There are several other synonyms for this phrase, including "slay," "execute," "murder," "assassinate," "annihilate," "eradicate," "eliminate," "butcher," "massacre," and "destroy." Each of these words conveys a sense of finality and violence, and should be used with care. Depending on the context, some synonyms may be more appropriate than others. For instance, "execute" is commonly used in legal contexts, while "massacre" implies that multiple people were killed at once. Ultimately, choosing the right synonym is important for conveying the intended meaning of a sentence.