### Clue: Garment from River Island splitting time and time again (3,5)
### Answer: TEE SHIRT 
 ### Explanation: Definition: Garment
 TEES(the English river) + I(abbrev. for "island") **contained in**(splitting) [ HR(abbrev. for "hour", a period of time) **plus**(and … again) T(symbol for "time" in physics) ].