Work out what the bullying is buying the cat
A cat who swats, ambushes, or blocks a dog is usually getting something out of it: the thrill of a chase she controls, ownership of a doorway or feeding area, or relief from boredom in a house where nothing else moves interestingly. Watch where it happens. Ambushes from the same hallway corner suggest a hunting game aimed at a predictable target. Blocking the dog from a room, the garden door, or his bed suggests resource control. Chasing a dog who then runs squealing adds excitement that reinforces the habit. The pattern matters because each version needs a slightly different fix, and punishing the cat teaches none of them anything except that people near the dog are also unpredictable. Note the locations and times for a few days before changing anything, and you will usually see the behaviour is far less random than it feels.
Redesign the routes so the dog can always leave
A dog who can walk away rarely needs to defend himself, and a cat whose ambush target keeps calmly disappearing loses interest in the game. Open up escape routes by moving furniture that creates dead ends, keeping doors between main rooms open or fitted so the dog can pass, and never feeding or settling the dog in a corner the cat can control. Give the cat vertical territory of her own: a tall scratching post, a shelf run, or the top of a stable bookcase where she can survey the dog from above, because cats who can go up usually feel less need to hold ground at floor level. Feed the two animals in separate areas with a closed door between them, since food guarding escalates faster than almost any other trigger and can turn a swatting habit into a genuine fight.
Interrupt early and pay the better choice
Step in at the stare, not at the swat. A fixed stare, crouched stillness, or a tail beginning to twitch at the dog are your cues to call the cat away cheerfully, toss a toy in the opposite direction, or place a cushion between the pair. When she turns to the toy or hops onto her perch instead, reward that choice with a treat or a short game, so choosing the alternative becomes its own habit. Give her a proper hunting outlet every day with wand play that ends in a meal, because a cat whose predatory needs are met on toys has less reason to schedule the dog. Keep interruptions boring and consistent from everyone in the house; laughing at an ambush or shouting at the cat both feed the drama that keeps it going.
Protect the dog's confidence while the work goes on
Check honestly how the dog is coping. A dog who hesitates at doorways, avoids rooms the cat favours, startles at movement, or has started snapping warnings needs the pair separated when nobody is supervising, with baby gates or closed doors rather than hope. Retaliation is the real danger in these households, because a dog who finally turns can injure a cat in seconds. If the cat's behaviour appeared suddenly, if she is also more irritable with people, or if she is eating or grooming differently, book a veterinarian visit before assuming it is attitude, since pain or an underlying illness can lower a cat's tolerance sharply. Escalating cases benefit from a qualified behaviour professional who can watch the pair at home. Using KinsLe, Care Teams lets you assign who supervises shared time, who feeds the animals apart, and who runs the cat's daily hunt session, with completions timestamped so gaps are easy to spot.