My current http access file is

# Pound sign comments a line out

# Disallow viewing of htaccess files
<Files .htaccess>
order allow,deny
deny from all

Options +FollowSymLinks
RewriteEngine On

# enable hiding php extension
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule ^(.*)$ $1.php 

At this time it simply hides the .php, i still wish to hide the .php but allow website/user/Username

Here you decide to go:

RewriteEngine On
RewriteRule ^user/(.*) profile.php?user=$1 [L]