And that's definitely because the whole door has dropped rather than it having gone out of shape (just one side dropped) or something loose (eg hinges meaning door now hangs slanted)?
You can adjust latterally with that centre nut with an SFS spanner, up and down is with a bolt under the hinge pin however it looks as though your door needs toe and heeling not hinge adjustments
And that's definitely because the whole door has dropped rather than it having gone out of shape (just one side dropped) or something loose (eg hinges meaning door now hangs slanted)?
Most likely it's not square to the frame either because the gap is only on one side so I guess a sideways adjustment will be needed to square it up first.
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