Source

File: wp-includes/comment.php

function wp_get_comment_status( $comment_id ) {
	$comment = get_comment( $comment_id );
	if ( ! $comment ) {
		return false;
	}

	$approved = $comment->comment_approved;

	if ( null == $approved ) {
		return false;
	} elseif ( '1' == $approved ) {
		return 'approved';
	} elseif ( '0' == $approved ) {
		return 'unapproved';
	} elseif ( 'spam' === $approved ) {
		return 'spam';
	} elseif ( 'trash' === $approved ) {
		return 'trash';
	} else {
		return false;
	}
}