unstressed

adjective

1. without stress or emphasis, as a syllable in a word.
2. not receiving or subjected to stress, wear, etc.: the unstressed parts of a car body.

adjective

1. carrying relatively little stress; unemphasized
2. phonetics of, relating to, or denoting the weakest accent in a word or breath group, which in some languages, such as English or German, is also associated with a reduction in vowel quality to a centralized (i) or (a)
3. prosody (of a syllable in verse) having no stress or accent