The most common and most likely answer to this crossword clue is the 7 letter word YELLOWS
Y
E
L
L
O
W
S
More clues leading to the result YELLOWS
- Building slowly absorbing earth goes off-white
- Field swirls with blues and other colours
- Two pointers at the table given chicken beginning to slobber
- Cooked well, soy becomes sickly-looking
- Chicken given supplements ultimately displays signs of ageing
- Cries about nothing and wife colours
- Daffodil and primrose, say, almost entirely grown facing north at bottom of yard
- Non-whites trapped by shells from batteries?
- Colours the old permits without top rung
- Chicken 65 for starters gets a shade timeworn
Buddy explains!

The straight part
We know that "becomes sickly-looking" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case becomes sickly-looking = yellows.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 YELLOWS mean?
YELLOWS noun- The colour of gold, butter, or a lemon; the colour obtained by mixing green and red light, or by subtracting blue from white light.
- The intermediate light in a set of three traffic lights, the illumination of which indicates that drivers should stop short of the intersection if it is safe to do so.
- One of the colour balls used in snooker, with a value of 2 points.
- (pocket billiards) One of two groups of object balls, or a ball from that group, as used in the principally British version of pool that makes use of unnumbered balls (the (yellow(s) and red(s)); contrast stripes and solids in the originally American version with numbered balls).
- A yellow card.
- Any of various pierid butterflies of the subfamily Coliadinae, especially the yellow coloured species. Compare sulphur.
- To become yellow or more yellow.
- To make (something) yellow or more yellow.