The purpose of this paper is to show the ways in which semantic and pragmatic restrictions operate on two very different types of interjectional expression. The paper focusses first on the difference between the expressions God knows and Goodness knows. A superficial glance at their use may seem to reinforce the general perception that they are easily substitutable for one another. However, a closer analysis reveals that the differences between them go beyond a difference in the level of emotional intensity expressed, and that each expression is associated with a particular attitude reflecting the extent to which the speaker does know something. For this reason they are not always easily substitutable for one another. The paper then focusses on one word, bloody, which functions in three syntactic positions. It is shown that a different illocutionary force is expressed depending on the syntactic position in which bloody occurs. At the same time, certain common semantic elements are retained regardless of the syntactic position.