spec 
(spĕk) Informal
(spĕk) Informal n.
1. specs The specifications, as for a building to be constructed.
2. Speculation.
tr.v. spec'd, spec'ing, specs or specced (spĕkt) or spec·cing (spĕkĭng)
To write or supply specifications for.
adj.
Idiom: 1. Of or relating to specifications: a manufacturer's spec sheet.
2. Done, constructed, produced, or purchased as a speculation: a spec job; a spec house.
on spec
On a speculation basis; with no assurance of profit: houses built on spec; writes TV commercials on spec.
spec'er n.