The word "不久前" is formed through a logical, step-by-step combination of its constituent morphemes: it begins with the negation "不" (bù, not), which modifies the adjective "久" (jiǔ, a long time), creating the phrase "不久" meaning "not a long time". This temporal phrase is then directly linked to the directional/locative character "前" (qián, before/ago), so the entire construction "不久前" literally parses as "before [a point that was] not long [from now]", which functions as a fixed adverb phrase meaning "not long ago".