He is junior ______ me.

Concept

A small group of comparative adjectives borrowed from Latin and ending in -or — junior, senior, superior, inferior, prior, posterior — do not follow the usual English comparison pattern with "than". By convention they are followed by the preposition "to" when one thing is compared with another in rank, age, or position.

Application

The sentence "He is junior ______ me" compares two people by seniority using the Latin-origin adjective "junior". Applying the rule, the correct linking preposition is "to", giving "He is junior to me".

Contrast

• "than" — used with ordinary comparatives like taller/older, but never with -or adjectives such as junior.

• "with" — shows accompaniment, not comparison of rank.

• "from" — marks source or separation, not a seniority comparison.

Cross-check: the same -or adjectives confirm the pattern — senior to, superior to, inferior to, prior to — all take "to", which is why "junior to" is the standard form.