By taking into account the psychoanalytic distinction between consciousness and the unconscious, we should distinguish two kinds of engagement . That’s what I’ll do in this text.
Imagine you are reading a difficult philosophical text. When you are actively following the sentences, being able to discern their implications, it means that you are consciously engaging with the text. Another example of conscious engagement is when you actively follow a certain political party or a certain publication with particular lines of thought. Another example of conscious engagement is when you love someone (e.g. your girl/boy friend) and openly declare your love. I call such a position “symbolic engagement” which is also called a “relationship”. When you have any kind of symbolic engagement, it is likely that you keep in your mind a set of thoughts and ideas associated with this particular engagement of yours, and that you would have something to say about it if the topic comes up, or at least declare your interest, so that what you will say can evidence your symbolic engagement. The symbolic engagements with something/someone also serves to prove the existence and the significance of that thing/person. The institutionalization of such a relationship is an “academic” whose job is to sustain and improve a number of active symbolic engagements with certain “topics” in certain “fields of study”.
The great secret about symbolic engagement is that it doesn’t exist (Lacan: “There is no sexual relationship”) and that’s why a man’s relationship with and love for a woman cannot prove her symbolic existence (Lacan: “Woman doesn’t exist”). And that’s also why many academics suffer from the so-called “impostor syndrome”. Of course, a woman (like a man) has a real existence (Lacan: “ex-sistence”) but this real existence can only take place in opposition to her symbolic engagements: Her real existence is only proven when her symbolic engagements go wrong. Her symbolic engagements take form as a defence mechanism against her real existence which comes prior to those symbolic engagements and cause them to fail. In other words, her real existence causes a symbolic disengagement, which is not truly a full disengagement. The psychoanalytic notion of the unconscious can be summarized in this formula: Symbolic disengagement is real engagement.
Now imagine that you have lost your conscious engagement: You are emptily staring at the paragraphs of the heavy philosophical text that you were reading. You have become unable to follow the meetings of that political party, or you can no longer follow the lines of thought in that publication. Or, you can no longer say you love him/her (like the scene in A Woman Under The Influence: “Do you love me?” “I, uh… I, uh… Now let’s go clean up that crap.”). You might seem to have been distracted by an external cause (so that “There is another party, another man/woman” etc.) but is that really the case? (as Lacan says, “There is no Other”) It is highly likely that the cause is immanent: The object overwhelms or outgrows your symbolic engagement with it, thereby disproving your relationship or love. The previously engaged object still participates in your psyche, it’s just repressed or disavowed.
So you are emptily staring at the paragraph because those sentences triggered other “irrelevant” thoughts associated with its signifiers. Or you cannot stand the political meetings because the topics push you to think “irrelevant” things. Or you are uncomfortable with him/her because you become irritated and agitated of his/her particular behaviors without a rational reason. What disproves, bungles or destroys symbolic engagement is another kind of engagement that I call “real engagement”. It comes from the unconscious and it’s an inherently negative force. Real engagement is perceived as anxiety. It is a deep relevance that is thinly disguised as an irrelevance. A psychoanalyst can see through the disguise and interpret it to reveal its relevance.
So what is conscious symbolic engagement? It’s a defence mechanism against unconscious real engagement. It relies on keeping up positive and negative fetishes (good and bad objects) that provide a screen to protect oneself from the real existence of the object. When such engaging fetishes fall along with all their backups, what manifests is a symbolic disengagement that is called a symptom. A symptom is symbolically unauthorized because symbolic authorization fails without the fetishes. It requires a “real authorization” (self-authorization) that relies on interpreting its relevance to the subject’s will or desire. 
Losing the symbolic conscious engagement is a simple negation that points to a real unconscious engagement. It’s like the melancholy that stages the loss of an impossible object to nonetheless appropriate it in fantasy.  Symbolic mourning as the isolation of a melancholic desire in a “memorial” is a symbolic defence against the real engagement of melancholy.  Melancholy says “it’s lost”. Symbolic mourning says “it’s not completely lost”.
One can also lose the real engagement (lose the loss) itself, which amounts to the negation of a negation: Real mourning as the metonymy of desire itself, disengaged from the particular objects. Real mourning says “it never existed”.
 I previously defined “effort” as “engaged labor-power”, see “Effort is engaged labor-power”