The most common and most likely answer to this crossword clue is the 4 letter word OILY
O
I
L
Y
More clues leading to the result OILY
- Unctuous and cunning when wife’s over
- Socially, oddly withdrawn and unctuous
- Like olives? Only in last year, primarily
- Greasy or dirty
- Lacy mat daughter's given away, soaked in viscous liquid
- Greasy old cycle is regularly brought back
- Obsequious sort of fish
- After regular dismissals, jovially unctuous
- Smarmy, jovially but regularly self-effacing
- Like lardy-cake, or what it’s served on, without topping?
Buddy explains!

The straight part
We know that "Like lardy-cake" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case like lardy-cake = oily.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 OILY mean?
OILY noun- A marble with an oily lustre.
- (in the plural) Oilskins. (waterproof garment)
- Relating to or resembling oil.
- Covered with or containing oil.
- Excessively friendly or polite but insincere.