Question: How do I replace current word under cursor in Emacs? 

I know that I can use query-replace or replace-string but every time I do so I have to type entire string to be replaced, this is just annoying. 

Vi has equivalent command cword and I can use a shortcut to pull the word under cursor for replacement:

```
nmap <leader>z :%s#\<<C-r>=expand("<cword>")<CR>\>#

```

Anybody know how to do it with Emacs?

Answer: 
I'm absolutely new to emacs but I can suggest the following:

```
M-b       to move backward over a word
M-d       to kill up to the end of the word

```

Now you can write a new word. Works almost like `cw` in vim
If you go into search-and-replace with `M-S-%` just pressing `M-n` fills in word under cursor, pressing it again wraps it in "symbol delimiter".