Override themes functions - php

Question

In my theme there is a functions-template.php file with a lot of functions. One of them echoes the category description on the site.
function woocommerce_taxonomy_archive_description() {
if ( is_tax( array( 'product_cat', 'product_tag' ) ) && get_query_var( 'paged' ) == 0 ) {
global $wp_query;
$cat = $wp_query->get_queried_object();
$thumbnail_id = get_woocommerce_term_meta( $cat->term_id, 'thumbnail_id', true );
$image = wp_get_attachment_image_src( $thumbnail_id, 'full' );
$description = apply_filters( 'the_content', term_description() );
if ( $image && yit_get_option( 'shop-category-image' ) == 1 ) {
echo '<div class="term-header-image"><img src="' . $image[0] . '" width="' . $image[1] . '" height="' . $image[1] . '" alt="' . $cat->name . '" /></div>';
}
if ( $description ) {
echo '<div class="term-description">' . $description . '</div>';
}
}
}
I want to echo another variable instead without messing with the files. Is there a way to "override" an existing function?
I've been fiddling a bit with mu-plugins etc but with no success.
I always get the Fatal error: Cannot redeclare woocommerce_taxonomy_archive_description() (previously declared in error when adding the same function in my custom functions file..

Answer 1

Yes it can be overridden from a child theme. You can override the function from your child themes functions.php file.
See more about child theme https://codex.wordpress.org/Child_Themes
WordPress loads child theme first and then the parent theme. So if you create a function with same name in your child theme, then the if condition with ! function_exists will will be false and hence there this function won't be declared.
If you want to override from a plugin then you've to declare the function in earlier execution. Try declaring it in a init hook.
add_action('init', 'theme_func_override', 5);
function theme_func_override(){
function override_func(){
//code goes here
}
}
Update
If the function isn't declared with function_exists() check within a if condition then you can't override it!