The most common and most likely answer to this crossword clue is the 5 letter word ICIER
I've seen this crossword clue in The Guardian
I
C
I
E
R
More clues leading to the result ICIER
- Ditch, I hear, with predictable exceptions gets more slippery
- Even less friendly company once meeting Queen
- Comparatively risky to ignore daughter becoming more aloof
- Dearer pair relinquished? More reserved
- Circuiteer in places that are even more distant
- . More hostile French here before the Queen
- . Less welcoming here in Calais leading to hesitation
- Here in France leading lady is increasingly aloof
- Relatively cold island, about one centigrade to the west
- Since I wear layers, it’s more cold
Buddy explains!

The straight part
We know that "more aloof" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case more aloof = icier.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 ICIER mean?
ICIER adjective- Pertaining to, resembling, or abounding in ice; cold; frosty.
- Covered with ice, wholly or partially.
- Characterized by coldness of manner; frigid; cold.
- To be wearing an excessive amount of jewelry, especially of the high-quality and expensive kind.