His colleagues suspected him of social-climbing when he started inviting company executives to dinner regularly.

social-climbing 是由 social（社交的）和 climbing（攀爬）组成的复合词。social 指"社交的、社会的"，climbing 来自动词 climb，意思是"攀爬、攀登"。 social-climbing 是一个固定表达，指"通过结交社会地位更高的人来提升自己的社会地位"，即"攀附权贵"的行为。