Nonsense and gibberish are both terms for speech or writing that makes no sense. Nonsense suggests a lack of meaning or logic, while gibberish is completely unintelligible speech or writing that may not even be in a language. Someone speaking in tongues, or simply in a language you don’t know, may as well be speaking gibberish. Gibberish more commonly refers to speech, deriving as it does from the verb “to gibber,” which means to speak inarticulately or meaninglessly, but it is also used of writing that is so full of obscure terms or jargon that it is impenetrable.
To end is to cease something or to come to a conclusion. Stories end, days end, and lives end. The things themselves, in these examples, have intrinsic beginnings and endings, and to end is a natural, organic outcome. Terminate suggests an immediate or abrupt stop imposed upon something, often by impersonal forces. It has a more official and technical feel. A contract, agreement, or license may be terminated before its expiration date. A judge may rule to terminate parental rights. To cap it all off, two extended senses of terminate have emerged: terminating someone can either mean to fire them or to assassinate them.
For talking about things physically extending far down or far back in space, deep is almost always the appropriate word (a deep well, deep shelves, a deep cut). Profound is more elevated diction reserved for awe-invoking depths (profound depths of the sea). Both adjectives can also be used figuratively, of feeling and thought: we admire the deep thinkers and profound poets for their ability to penetrate beyond surface impressions and discover truths inaccessible to most of us. However, deep is more informal and used in this way can come off as a bit sophomoric (Wow, that’s a deep poem.) Profound suggests with more authority something’s intellectual significance (profound ideas or insights). In general usage, profound is most frequently used to describe change and its effects. In this context, profound implies far-reaching, transformative, significant, fundamental, or lasting (profound change, profound impact, profound influence).