Full Idea
We construct a sense out of its constituents and introduce an entirely new sign to express this sense. This may be called a 'constructive definition', but we prefer to call it a 'definition' tout court. It contrasts with an 'analytic' definition.
Gist of Idea
A 'constructive' (as opposed to 'analytic') definition creates a new sign
Source
Gottlob Frege (Logic in Mathematics [1914], p.210)
Book Reference
Frege,Gottlob: 'Posthumous Writings', ed/tr. Hermes/Long/White etc [Blackwell 1979], p.210
A Reaction
An analytic definition is evidently a deconstruction of a past constructive definition. Fregean definition is a creative activity.