Possible Clues:

• Work unit across river, say
• Unit of work (phys.)
• Just a little work and nothing more, therefore
• As for 'er, gee, you'll get little work from 'er!
• Work unit used by some energetic sportsmen
• So little a bit of work comes to nothing therefore
• Physicist's unit
• A bit of work done in an emergency
• It's just for work and needs nothing more, therefore
• Sandy desert area