する(せっする) Direct contact. Like the mobster says, “Never contact me directly, always talk to my Consigliore.” Or “The building directly contacts the buildings on either side of it.”
(ちょくせつ) Direct – communicating directly as opposed to communicating with hints and insinuations. To take direct action (i.e. a protest) as opposed to writing letters to one’s congressperson.   $$$
つなぐ To connect two things, in a way that is not easily separated:train cars, for instance. But also holding hands.
(ちょくに) To be directly pressed against – usually used with objects. For instance, “Don’t put the chair directly on the floor, it’ll scratch. Put the chair on this throw-rug.” or, “Don’t put the coat on the baby directly, he’s allergic to wool. Put this nylon undershirt on him and THEN put the coat on.” Unlike the related word つなぐ、 直に refers to things that are not connected or bonded to each other, it refers to adjacent, moveable layers.