Boffin

n.capable, thoughtfulplayful

What it means

A scientist or technical expert, named in informal British English.

Reach for it when referring playfully to deep scientific or technical expertise

A battery boffin traced the fault to a damaged temperature sensor.

playful
egghead
teasing language about intellectual ability is welcome within the group
not when Without established rapport, egghead is more likely to insult than praise.
playful
whiz
quick impressive skill suits an affectionate informal voice
not when Whiz can sound childish and may praise speed more than depth.
professional
expert
high knowledge in any relevant field is enough
not when Expert is broad and lacks boffin's technical flavor.
professional
researcher
systematic investigation defines the work
not when A researcher may be junior or nonspecialist and need not be technical.
professional
scientist
the person conducts scientific research
not when Scientist is inaccurate for an expert engineer or technician.
formal
technical specialist
the role and expertise need precise neutral wording
not when The phrase is impersonal and does not convey inventive curiosity.

computer boffin
A computer boffin recovered the archive from the damaged drive.
science boffin
The science boffin made the demonstration safe for younger pupils.
technical boffin
A technical boffin redesigned the valve with two common parts.

Boffin is informal British English and can sound affectionate, reductive, or dated depending on context.

The definition and the example on this page are written here. The dictionaries above ground which meaning is being described, not the wording.