Search only by Field instead of entire content
Give this a go:

{% set searchTerm = craft.request.getParam('q') %}    
{% set query = craft.entries({
        search: 'title:*' ~ searchTerm ~ '*',
        limit: 5,
        locale: craft.locale,
        order: 'score'
    }) %}


You can leave out the * on both sides if you only want to search for full word matches. Also, this might help you take it further: https://craftcms.com/docs/searching