The most common and most likely answer to this crossword clue is the 6 letter word VEINED
V
E
I
N
E
D
Buddy explains!
The straight part
We know that "Streaked" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case streaked = veined.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does VEINED mean?
VEINED verb- To mark with veins or a vein-like pattern.
- (sometimes in combination) Having veins or veinlike markings.