Entry 2 senses · 2 variants Webster, 1913 Obstruent · Ob·stru·ent · IPA /ˈɒbstɹuːənt/ a. n. 01 a. Causing obstruction; blocking up; hindering; as, an obstruent medicine. 1. Causing obstruction; blocking up; hindering; as, an obstruent medicine. 02 n. Anything that obstructs or closes a passage; esp., that which obstructs natural passages in the body; as, a medicine which acts as an obstruent. 1. Anything that obstructs or closes a passage; esp., that which obstructs natural passages in the body; as, a medicine which acts as an obstruent.