na-adjective, noun
vexatious; troublesome; complicated
Describes a situation, procedure, or matter that is annoyingly complicated, full of petty details, or causes irritation due to its complexity. Somewhat formal and literary.
この申請手続きは煩瑣で、何度も書類を書き直させられた。
This application procedure is vexatiously complicated, and I was made to rewrite the documents many times.
煩瑣な規則に縛られて、仕事がなかなか進まない。
Bound by troublesome rules, the work just won't move forward.
面倒 is a common, everyday word for 'troublesome' or 'bothersome'. 煩瑣 is more formal and emphasizes petty, annoying complexity rather than simple bother.
煩雑 also means 'complicated' or 'troublesome', but is more common and less literary than 煩瑣. 煩瑣 carries a stronger nuance of being vexatious due to excessive detail.
Compound of 煩 (annoyance, trouble) and 瑣 (trivial, petty). The combination suggests trouble arising from petty or overly detailed matters.