All you need to do is type
alias at the prompt and any active aliases will be listed.
Aliases are usually loaded at initialization of your shell so look in
.bashrc in your home directory.
unalias will only work for your current session. Unless you find where it is defined and loaded, it will be loaded again when you start a new Terminal session.
~/.bashrc gets run for both login and non-login shells,
~/.bash_profile only gets run for login shells.
See login shell vs non-login shell
As per comment from Chris Page:
You should put most of your customizations (including aliases) in
~/.bashrc and have
~/.bashrc, so they apply to both login
(~/.bash_profile) and non-login
(~/.bashrc) shells. Also, decide which of these should be "primary" and if the profile is your choice, tack on the rc file at the end. If the rc file is primary, source that at the beginning of your profile
These lines should be in the file
if [ -f "$HOME/.bashrc" ] ; then
This will include
~/.bashrc for login shells and in the order you wish if one file depends upon the other based on what you are setting.