expression, adverb
for show; just for appearance; not just for nothing
Used adverbially, almost always with a negative verb, to mean that something is not done merely for show or without substance. Often in the pattern 伊達に〜ない.
彼は伊達に長年この仕事をしているわけではない。
He hasn't been doing this job for years just for show.
伊達に毎日練習しているんじゃない。
I don't practice every day just for appearances.