what is the best reply if someone ask u "what are you wearing"
Depends.
If it's their first email, then don't reply.
If you've been chatting for a while and you're both sharing some kind of tension, they ask with a "lol," then either answer with something sexy, the truth, make a joke out of it, or don't reply.
If you've been chatting for a while, and you're hoping to meet, then tell them "you'd know if you'd ask me out."
If it's your date and they are highly confused by your mermaid swan raw meat coat you can tell them all about your personal fashion.
If you've invited someone to something and they ask that, then tell them the dress code or expectations for the event.
If it's your dad then put on some pants and a sweater and wipe that makeup off your face.
If you're standing on a red carpet and someone with a microphone and a cameraman asks that, then tell them the designer and how wonderful it is.
If it's your boss ask "I guess this isn't conforming to the dress code?"
If aliens abduct you and ask, tell them about the wonders of textiles.
Unless they seem meek and obsequious.
Then tell them the flesh of your enemies.
Or just tell everyone that.