buttonholing

/B AH1 T AH0 N HH OW0 L IH0 NG/
verb
  1. 1

    To detain (a person) in conversation against their will.

Synonyms

noun
  1. 1

    The act of detaining someone in conversation against his or her will.

Source: https://en.wiktionary.org/wiki/buttonhole, https://en.wiktionary.org/wiki/buttonholing