My prefix is a winner.
My suffix is the inner.
My infix is whole.
My whole is cold.
Prefix "pass", what the winner has done to everyone else in a race
Suffix "less", a number less than x is inside the set of natural numbers up to x
Infix "ion", a perfectly whole bit of matter, though I grant the missing electron may make this a stretch
Passionless means "cold or unemotional"