闭门造车

闭门造车 [bì mén zào chē]

1. ■ shut oneself up in a room making a cart; carry out one's idea irrespective of external circumstances; divorce oneself from the masses and from reality and act blindly; do whatever one likes individually， oblivious of the world; draw up plans behind closed doors; indulge in fantasy (to build air castles); make a cart behind closed doors;work behind closed doors;work on [at] some project without reference to what the world requires [needs]