Tough-movement

Definition
Tough-movement is the kind of movement that has been assumed in the derivation of sentences such as (i), which are headed by predicates like tough and easy.

(i)   John is easy to please

If the adjective easy assigns no external theta-role, one is led (by the theta-criterion) to assume that the subject John has been moved out of the object position eiof please:

(ii) *Johniis easy [CP PRO to please ei]

However, such an analysis is excluded, either as a case of improper movement, or as a binding violation. As a solution it has been proposed that John in (i) is an argument of the adjective easy, and that the CP is a modifying adjunct:

(iii) Johni is easy [CP Oi [PRO to please ei]]

The object of to please, then, is a variable bound by the empty operator O which is coindexed with John. Easy to confuse with though-movement though it is, it is different.

Links

 * Utrecht Lexicon of Linguistics