Final answer:
The profession sign without the "person" ending is "principal", which doesn't end with the typical -er, -or, or -ian suffix, unlike "teacher", "counselor", and "librarian".
Step-by-step explanation:
The profession sign that does not use the "person" ending is "principal". This term typically refers to the head administrator of a school and does not end with the common -er or -or suffix that denotes a person carrying out a profession or activity, such as "teacher" or "counselor". On the other hand, "librarian" does incorporate the -ian suffix, which also indicates a person characterized by a certain thing or quality.