English Reference
Phrasal verb

fill in for

phrasal verb.
B1 Intermediate Oxford

phrasal verb.to do someone else's work for a short time because they are away or sick.

phrasal verb.to act as a temporary substitute for someone; typically used in professional or social contexts to denote a short-term replacement.


SIMPLE

Can you fill in for me while I'm at the doctor?

CONTEXTUAL

The assistant manager had to fill in for the director during her three-week maternity leave.

COMPLEX

Despite having little experience in logistics, Sarah was asked to fill in for the department head during the emergency summit.

Usage

usually followed by a person; implies the substitution is temporary.

Teaching tip

contrast with 'stand in for' (very similar) and 'replace' (which often implies a permanent change); 'fill in' without 'for' can also mean to complete a form.

Pitfall
I will fill in for his job.I will fill in for him.

you fill in for a person, not for a task or a position; you 'fill' a position but 'fill in for' a colleague.

Particles
in for
Separability
inseparable
Pattern
fill + in + for + object
This entry
Level B1 · Intermediate
Updated