Learn Turkish: O tekinsiz adam hakkında birtakım yalanlar uydurup duruyorlar. - They keep making up a number of lies about that eerie man.

When written as a single word, birtakım is a vague quantity determiner meaning "some," "certain," or "a number of." Even though it contains the word bir (one), it acts similarly to bazı (some) and requires the noun that follows it to be plural, hence yalanlar (lies). If it were written separately as bir takım, it would literally mean "one team" or "one suit" and would be followed by a singular noun.

How does the verb structure in uydurup duruyorlar mean "they keep making up"?

This uses the continuous/repeated action structure: Verb + -(y)ıp/ip/up/üp + durmak. It describes an action that happens over and over again, often conveying a sense of annoyance or complaint from the speaker. Here, uydurmak (to make up / fabricate) takes the connecting suffix -up, and the auxiliary verb durmak provides the meaning of "to keep on doing it."

What exactly does the word tekinsiz mean, and how is it formed?

It translates to "eerie," "sinister," or "creepy." It is built from the noun tekin, which means "safe," "auspicious," or "reliable." By adding the suffix -siz (without), you get tekinsiz—describing someone or something that gives you a bad feeling or doesn't seem safe to be around.

Why does the sentence use adam hakkında instead of the genitive ?