The most common and most likely answer to this crossword clue is the 10 letter word SYCOPHANTS
I've seen this crossword clue in The Guardian
S
Y
C
O
P
H
A
N
T
S
Buddy explains!

The straight part
We know that "who toady" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case who toady = sycophants.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 SYCOPHANTS mean?
SYCOPHANTS noun- One who uses obsequious compliments to gain self-serving favor or advantage from another; a servile flatterer.
- One who seeks to gain through the powerful and influential.
- An informer; a talebearer.