The route reaches the final bridge POMP, then changes letter 3 to reach POOP. Its 6 moves match the dictionary distance calculated from the target.
Compare the first move
BUSY has 5 accepted one-letter neighbors in this vocabulary. 3 can begin a shortest route: BURY, BUSK, BUST. Each leaves exactly 5 moves to POOP.
Some longer openings are BUOY (7 total moves), BUSH (7 total moves). These counts include the first move from BUSY.
Similarity can be misleading
BUSY → BURY, BURP → BUMP do not reduce the number of letters that differ from POOP, but still belong to a minimum-move route. Reachable word connections matter more than matching letters immediately.
If a word is rejected
Enter the last accepted word in the solver, exclude the rejected word, and recalculate. A shorter dictionary can require more moves. Read the strategy guide for a worked detour example.