monosyllabic

/ˌˈmɑnəsəˌlæbɪk/

Any word or sound made up of just one syllable can be described with the adjective monosyllabic.

Monosyllabic comes from the Greek prefix monos, "single," and syllabē, used to mean any collection of vocal sounds taken together to be uttered in a single breath — a syllable. You can also describe the replies or speaking style of a person who tends to talk using grunts or short words, as monosyllabic, like your cranky old grandpa's curt responses to the questions of a newly verbal toddler: "Yes," "No," "Huh?"

Definitions of monosyllabic

1. adjective

   having or consisting of only one vowel or vowel-like sound, with or without consonants surrounding it
   synonyms:

   syllabic

   consisting of a syllable or syllables