Despite his announced intention to present a "full dress analysis of the illocutionary act", Searle in fact does not give one.
It may be thought of, in a sense, as the effect of the illocutionary act via the locutionary act.
An illocutionary act consists of five elements: Speaker, hearer, time, location and circumstances.
Asking a question is an example of what Austin called an illocutionary act.
To perform an illocutionary act is to use a locution with a certain force.
The concept of an illocutionary act is central to the concept of a speech act.
The primary illocutionary act is the indirect one, which is not literally performed.
All of these three acts, but especially the "illocutionary act", are nowadays commonly classified as "speech acts".
Breaking a social taboo can act as an emotional release with the illocutionary act of expressing a feeling or attitude.
If someone says, "It sure is cold in here", there are several different illocutionary acts that might be aimed at by the utterance.