Approve / Approve of
UsageApprove something means formally authorise it; approve of something means have a favourable opinion of it.
Approve
Use when
You mean formally authorise, accept or sanction something.
Example
“The board approved the revised budget.”
Approve of
Use when
You mean regard something as good, acceptable or morally right.
Example
“Most respondents approved of the simpler application process.”
Quick check
approve of the budget, approved the behaviour
Usage note