knee–jerk

knee–jerk /ˈniːˌʤɚk/ adjective
knee–jerk
/ˈniːˌʤɚk/
adjective
Britannica Dictionary definition of KNEE–JERK
always used before a noun [more knee–jerk; most knee–jerk]
1 
: occurring quickly and without thought
2 
disapproving : often reacting quickly and without thought