Instop is a word that refers to the act of stopping something from moving forward, typically by blocking a passage or stopping a flow. The spelling of the word can be explained using the International Phonetic Alphabet (IPA) as /ɪn.stɒp/. The first syllable is pronounced as "in" and the second syllable rhymes with "stop". The use of the prefix "in-" indicates the opposing action of stopping something from moving forward, making instop the opposite of "start" or "begin".