What are synonyms for recon?

The term "recon" is not really a Word; it's not so much slang as it is just a shortened, informal version of the Words "reconnaissance" (a noun) and "reconnoiter" (a verb)-- depending on which one it means.

The gist of both Words, however, involves an inspection or assessment of a situation, so the Word "survey," which is spelled the same as both a noun and a verb, is probably the ideal synonym. You could substitute the Word "survey" for "recon" in any sentence, whether "recon" is being used to represent "reconnaissance" or "reconnoiter."