Meaning of “joined-up” - Learner’s Dictionary

joined-up

adjective uk /ˌdʒɔɪnˈdʌp/ UK
joined-up writing

a style of writing where each letter in a word is connected to the next one

joined-up thinking

thinking about a complicated problem in an intelligent and original way, and considering everything that is connected with it

(Definition of “joined-up” from the Cambridge Learner’s Dictionary © Cambridge University Press)