I don’t think I’m really qualified to answer this and tbh I’ve never heard the term before but 갖다 = to have and 붙이다 = to attach something to something. From the example sentences on naver dictionary and this article I’d say it either means a physical attachment such as

그가 그녀의 두 팔을 잡아 꼼짝 못하게 옆구리에 갖다 붙였다 (= He grabbed her arms and pinned them to her sides) or a more metaphorical attachment or ‘application’ of concepts such as terminology, role ect. (용어를 갖다 붙이다 = Apply the term…) If anyone else knows better please let us know :).