Is there a word(or a combination of 2 words) that describe someone who advances his career using solely underhandedly social relationships? [duplicate]

Solution 1:

Ingratiating, sycophantic, groveling, unctuous, obsequious, and other synonyms could apply to this situation.

These words are all synonyms of each other, so they all have (very) similar meanings.

Sycophantic is defined as:

behaving or done in an obsequious way in order to gain advantage. [Lexico]

Obsequious is defined as:

obedient or attentive to an excessive or servile degree. [Lexico]

I won't put the rest of the definitions because they are all essentially the same. However, the "best" word for this situation would likely be "sycophantic" because of the "to gain advantage" part of its definition; nonetheless, all of these words have that as a subtextual component.