umodes are set with the /mode command used on your own nickname.
For example, if your client recognized $nick as your current nickname, you may run /mode $nick -g to turn off caller id.

Oper Only Mode Description
No i Designates the client as "invisible".
No g Caller ID mode which only allows accepted clients to message you.
No w Can see wallops
Yes o Designates client as IRC Operator
Yes a Designates client as IRC Admin
Yes l Can see oper local wallops
Yes s Server Notices
Yes z Can see oper wallops
No C Prevents you from receiving CTCPs other than ACTION
No Q

Prevents you from being affected by channel forwarding

No Z

Connected via SSL (Cannot be set/unset).