Synonym for “Small but Obvious”?

Question

I’ve seen many works in which the phrase “small but obvious” is used. I understand and acknowledge the fact that it is, essentially, perfectly fine to simply use these precise words; however, I was wondering if there was a single word which accurately sums up the meaning of the phrase. I could swear that I’ve heard a term like it before, but I cannot for the life of me remember what it was.

I’ve already done a quick search on Google, but the entire first page of engine results were—primarily—synonyms and definitions of both “obvious” and “non-obvious”, through six links to online thesauri and dictionaries, respectively.

The other four referred me to online books, via Google Books; Systema Porifera: A Guide to the Classification of Sponges, Mammals of South America, Volume 2: Rodents, Vascular Flora of the Southeastern United States: Asteraceae, and The Proterozoic Biosphere: A Multidisciplinary Study.

. . . I’ve decided that I’ll most likely be best off in the long run if I simply avoid the content suggestions on the next pages.

Anyway! Just in case a provided example would make answering this easier, then this is the context in which I’m going to use it:

His breathing quickened, a [small yet obvious] change that hadn’t gone unnoticed by his friend.

Any feedback is appreciated, and comments are always welcome! Thanks for the help, everyone!

Answer 1

I believe the word you're looking for is subtle. With a slight modification to the original sentence to account for the contradiction in meaning (i.e. that it was both a slight and noticeable change), the term will do just fine.

Definition (Google):

(especially of a change or distinction) so delicate or precise as to be difficult to analyze or describe

Here's how I would rephrase your sentence:

His breathing quickened. Though it was a subtle change, it did not elude his observant friend.

Notice the addition of "though" compensates for the apparent contradiction that a keen reader would otherwise spot. Additionally, the characterization of his friend as one who is "observant" further clarifies your meaning.

I realize the term does not exactly fit your requisite, but to be fair, I don't think such a word exists (though I could be wrong).

Answer 2

Although its meaning is "small but valuable", perhaps 'modicum' would work.

See modicum at Oxford dictionary, defined as

A small quantity of a particular thing, especially something desirable or valuable

Answer 3

Perhaps you are thinking of perceptible. From Oxford Dictionaries:

ADJECTIVE (especially of a slight movement or change of state) able to be seen or noticed.

I think the implication of a slight movement or change of state might match what you mean by "small" and able to be seen or noticed is fairly close to "obvious" The adverb barely is often included for even tinier movements. So for your example:

His breathing quickened, a (barely) perceptible change that hadn’t gone unnoticed by his friend.