| Definition -
The inherent aspect that a word has because of the way it is used in the lexicon. For example, the verb work has an inherently unbounded aspect, which means that the speaker must actively constrain it, e.g. I
worked for an hour yesterday.
1. As opposed to grammatical aspect, which is the aspect that the speaker choses to give the statement — for example, a speaker choosing to see a situation either as bounded ("I ate") or unbounded ("I was eating").
Quotation - "Grammatical aspect points to subjectivity in the sense that the speaker makes use of morphological procedures to express a certain aspect, depending on his view of reality. For instance, the choice between perfective or imperfective verb tenses shows the speaker’s attitude towards a situation, considering it as a complete and finished action or as an incomplete one, respectively.
In contrast, lexical aspect makes reference to the inherent aspect that words have, which is already marked in the Lexicon."
(Source: Lexical aspect in predicative complements subcategorized by pseudo-copulative verbs by Eva Florencio (Seville University, Spain))