A long-time friend of the chairman said she had expected the resignation.

long-time 是由形容词 long（长的、久远的）和名词 time（时间）组成的复合形容词，意思为"长期的、长时间的"，通常用来形容持续多年的关系。long-time friend 意为"多年的朋友"或"老朋友"。