A student who has already received one degree and is studying at a university for a more advanced degree
undergraduate
postgraduate
pupil
Time worked in addition to your usual job hours
undertime
tome-out
overtime
Having more knowledge, skill, and/or experience than is needed (for a particular job)
underqualified
overqualified
multi-qualified
Happening twice a year
biannual
twice-annual
inter-annual
A person who has money and property worth several million dollars, pounds, euros, etc.
multimillionaire
bi-millionaire
billionaire
An occasion when someone buys or sells something
interaction
transaction
biaction
Intending or intended to produce a good result or avoid a problem, rather than waiting until there is a problem
reactive
proactive
overactive
To sleep for longer than you intended to and so wake up late
multisleep
undersleep
oversleep
Within an organization
multiternal
internal
external
A very short amount of time, usually important in some way
intermoment
micro-moment
mega-moment