Neon - ljóft

Neon (ljóft, ljós + loft), the gas which is a component of 'air' (loft), used in lighting (ljós). If the neologism ljörvi (laser) is acceptable as an acronym of ljós (light) and 'örvi (derived from the verb örva, stimulate), the so should be ljóft. It aso sound a bit like the adjective ljúfur (in the meaning of geðfelldur (agreeable, pleasing). Neon-light is indeed an pleasant sight.
The noble gases are commonly used in lighting because of their lack of chemical reactivity. Neon was the first in its group to be used for this purpose and its name with respect to lighting has been extended to other noble gases. Argon- or krypton-filled light-tubes are called 'neonlights' as well. It's slightly comparable to the chemical term 'salt', which originally denoted sodium chloride before its meaning was extended to 'any ionic compound, made from a metal cation and a non-metal anion'. In the same way we can extend the meaning of 'ljóft' to that of 'noble gas'.