An iambic pentameter line is a verse line of __

Blank verse: an iambic pentameter verse lines without rhyme at the end.
An iambic pentameter line is a verse line of five iambic feet. In blank verse, the last word of a line does not rhyme with the last word of any of the successive lines.
Poets and dramatists use blank verse to avoid the monotony of traditional rhyme schemes, to use a wide variety of different tones, to add elegance and to match the heroic or elevated voice.
[Source: An ABC of English Literature - Dr M Mofizar Rahman and Britannica]