(adjective) marked by lack of definite plan, regularity, or purpose / (adjective) not connected with the main subject / (adjective) disappointing in progress, performance, or quality
Instead, they threw parties that followed a rigid script: first the guys would watch porn while the girls chatted among themselves. When the groups did interact, the guys would make a desultory show of chivalrous ardor, rolling their eyes at one another when they could without the girls noticing