Beautiful, lovely, handsome, pretty, bonny, comely, fair, beauteous, pulchritudinous, good-looking are comparable when they express judgment of a person or a thing perceived or contemplated with sensuous or aesthetic pleasure.
Although they differ widely not only in their implications and connotations but also in their range of reference, they carry in common the meaning very pleasing or delightful to look at.
Of all these adjectives beautiful is usually the richest in significance; since the abstraction it represents (the beautiful) has been for many centuries the subject of discussion by philosophers, artists, and aestheticians, its content in a particular context often depends upon the speaker’s or writer’s cultural background, his chosen philosophy, or his own peculiar definition. In general, however, both in learned and in ordinary use beautiful is applied to what excites the keenest pleasure not only of the senses but also through the medium of the senses of mind and soul.
It also suggests an approach to or a realization of perfection, often specifically the imagined perfection associated with one’s conception of an ideal. That is why beautiful is applicable not only to things that are directly perceived by the senses, but to things that are actually mental constructions formed in the mind through the instrumentality of language or as a result of inferences from certain outward manifestations.
Lovely, like beautiful, usually suggests a more than sensuous pleasure, but it implies keen emotional delight rather than profound intellectual or spiritual pleasure. It is applied therefore to what is so pleasant to look upon, to hear, to smell, or to touch that the person affected dwells delightedly, sensuously, or amorously upon it or the sensations it produces.
Handsome, on the other hand, carries little connotation of emotional or spiritual pleasure; it implies rather a judgment of approval occasioned by something that is pleasant to look upon because it conforms to one’s conception of what is perfect in form and detail or in perfect taste, and pleasing because of its due proportions, symmetry, or elegance.
It is applied chiefly to what can be regarded unemotionally and with detachment; thus, a woman who is described as handsome rather than as beautiful or lovely is by implication one whose appearance aesthetically satisfies the observer but does not markedly stir his deeper feelings.
Pretty, in contrast to handsome, is applied largely to what pleases by its delicacy, grace, or charm rather than by its perfection or elegance of form or style. It is seldom used to describe something large or impressive; consequently it often connotes diminutiveness, daintiness, or exquisiteness.
Pretty is often used depreciatively to suggest mere pleasingness of appearance and the absence of qualities that make for beauty, grandeur, or strength.
Bonny, which is more common in British and especially Scottish use, implies approbation of a person’s or thing’s looks but it may also imply various pleasing qualities (as sweetness, simplicity, healthiness, plumpness).
Comely implies an opposition to what is homely and plain and suggests pleasant wholesomeness with a measure of good looks or physical attractiveness.
Fair applies especially to something which gives delight because of the purity, the flawlessness, or the freshness of its beauty.
Beauteous and pulchritudinous are used especially in ironic or journalistic prose where they often carry a suggestion of derogation or imply an emphasis on mere physical attractiveness.
Beauteous in poetical and dignified use often carries a stronger implication of opulence of charms than beautiful.
Good-looking is a less expressive word than handsome or pretty but is often used as a close synonym.