The most common and most likely answer to this crossword clue is the 5 plus 4 letter word LIGHT BULB
L
I
G
H
T
B
U
L
B
More clues leading to the result LIGHT BULB
- Easy to cry when rebuffed — and glower
- Shiner‘s mild swelling
- For a picture of inspiration, settle on daffodil?
- What’ll brighten up the room — pale daffodil, perhaps
- Bearer of moving charge fixed with bayonet?
- Cry raised after stairway loses fine source of illumination
- Easy to cry on retirement — this should brighten things up
Buddy explains!

The straight part
We know that "this should brighten things up" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case this should brighten things up = light bulb.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.