### Clue: Crooked Shakespearean character enters country from the south (8)
### Answer: DIAGONAL 
 ### Explanation: Definition: Crooked
 IAGO(character in Shakespeare's Othello) **contained in**(enters) **reversal of**(… from the south, in a down clue) LAND(a country).
On first pass, "crooked" doesn't seem synonymous with "diagonal". The former means bent or twisted, whilst the latter means straight but oblique, ie. neither horizontal nor vertical. But I suppose they could convey the same sense when used thus:  "That picture frame on the wall is crooked."