Remove specific words from SearchWP's default stopwords list without removing/replacing them all

functions.php

<?php

function my_searchwp_stopwords( $terms ) {
  
  // we DO NOT want to ignore 'first' so remove it from the list of common words
  $words_to_keep = array( 'first' );
  
  $terms = array_diff( $terms, $words_to_keep );
  
  return $terms;
}

add_filter( 'searchwp_stopwords', 'my_searchwp_stopwords' );