How to hide a product from a collection using liquid?

Store Design
4

Using Liquid will mean that your collection will have gaps in the product grid. For example if you show 50 items per page it would be possible to see 0 items if all 50 had the tag. You’ll 100% end up seeing a mix of numbers that might be very weird for the customer to see.

The concept would be:

{% for product in collection.products %}
  {% if product.tags contains 'outlet' %}{% continue %}{% endif %}
  <!-- your product grid item -->
{% endfor %}