What do we mean by deconstruction and structuralism? Give short and comprehensible definitions of both.

Both concepts have to do with what a text has to offer as
compared to how you read a text ( feminist criticism for instance is a way of reading a
text). Deconstruction originates in the 60s with Jaques Derrida's
work Grammatology. While Derrida never gives a precise definition
of Deconstruction, he argues that it is impossible to pinpoint the meaning
of a text because the text is full of internal contradictions. This does
not mean that characters contradict themselves, but rather
that a text is structured in a way that does not permit closure for a reader because it
is not a discrete whole.

Structuralism had already been in
use when Derrida wrote and it influenced his thinking. Structuralism originates with the
thinking of Ferdinand de Saussure who is considered the first semiotician. But the
foundational work of Structuralism was done by the Formalist School in Russia, the
Prague School and in France by Roland Barthes. There are other adherents though.
Structuralism derives from an attempt to give literary criticism a more scientific mode
of looking at a text.While it can be understood to be an intellectual movement, in terms
of literary analysis it means that a text reflects cultural structure,
which in turn is modeled on language. Hence, a text is reflective of the
culture it was produced in. Later on, Marxist critics would make use of this idea and
begin to argue that a text is reflective of
ideology.

Structuralism is very specific and formulaic at
times, forcing  close engagement with a text. Hope this helps.