(originally) a small state subordinate to a large feudal state; (modern) a country controlled or dominated by a more powerful nation; a satellite state
appendage
a person or thing that exists in a secondary or subordinate position; something that is dependent or parasitic on another thing
to tag along
to cling to or follow (a trend, person, or fashion); to mimic others blindly or affectedly, typically in the phrase 附庸风雅fùyōngfēngyǎ