mature age, develop, mellow, ripen
These words refer to the process of growing up or growing old. Mature is the most formal of these; in its most restricted sense, it indicates the natural attainment by a living thing of its adult or fullest form. [Caterpillars eventually mature into butterflies; Boys mature more slowly than girls, both physically and psychologically.] Outside this strict but neutral reference, the word can register approval for the gaining of wisdom, experience or sophistication, particularly when this process is not necessarily inevitable: childhood hardships that matured in him a precocious sense of responsibility.
Age, unlike mature, need not refer to fruition or tempering; instead, it more often refers to the changes that result from the mere passage of time: a study of how body tissue ages. The word can often, in fact, refer to negative or destructive changes that occur as a living thing grows old: lines and wrinkles that revealed how much she had aged since I saw her last. Mature is sometimes euphemistically substituted for age in this sense, as though the former’s positive reference to fruition might soften the latter’s presumed harshness in suggesting declining vigour: She had matured into a lovely grandmother. Age, however, can apply to man-made products with favourable force: whisky that has been properly aged. Here, it suggests valuable or desirable qualities that only time can impart. When applied to inanimate objects in general, age applies less positively to the attrition resulting from time’s passage: unpainted houses that had aged because of decades of exposure to the elements. Develop is more like the first sense of mature in pointing to positive change in which an existing or rudimentary form is improved, evolved or perfected. In referring to normal biological growth and change, the word can apply more generally than mature, since it can be used to refer to a part as well as a whole organism, and can indicate less ambiguously other transitions than the one culminating in adulthood. [When the breasts begin to develop, girls are already well on their way to maturing into young women; The foetus develops lungs relatively late in the gestation period.] When the word does not refer to predicable biological change, it is more general in application, most often referring either to the improvement or detailed elaboration of something: He joined a gym to develop his body; a committee set up to develop a programme for dealing effectively with air pollution.
Mellow concentrates on aspects of mature and age that pertain to the tempering imparted by time or experience. The word specifically suggests a reduction in harshness or the moderating of an extreme position: As they mature, many young radicals mellow into a more tolerant attitude towards life and society. In this sense, mellow is more positive than mature and age, since it gives overtones of glowing warmth, mildness and amiability.
Ripen is a less formal and more vivid term for mature, with the same reference to the attainment by something of its final or most developed form. At its most literal, the word applies to fruit, describing the process that brings it to its most usable or edible: applies that were green a week ago have already ripened. Metaphorically, the word often refers to the filling out or enlarging of a spatial form: the girl’s ripening body. Used in a more general way in reference to people, the word often suggests not the attainment of adulthood but a mellowing process in later life; here the word often points to a gain in wisdom, like one sense of mature, but is in less danger of being felt as euphemistic: Rembrandt slowly ripened into a command of the insights typical of his last great phase. Sometimes the word more simply refers to any sort of increase or growth: The reader’s interest is sure to ripen as he gets deeper into this new suspense novel.