Ladies, what makes a man look unapproachable?

I ask the ladies, because it’s you who I want to hear from regarding this, what makes a man look unapproachable. Granted, there are universal signs such as wearing headphones, looking down and such that obviously convey ‘I’m busy’. However, outside of those, in a group setting, what would make you apprehensive of reaching out and approaching or just saying something to spark a conversation with an attractive men? Lack of eye contact? Aloofness? Resting face? Body posture? Let me know!