Pretty ordinary when repeated thus (2-2)
I believe the answer is:
so-so
'pretty ordinary' is the definition.
'so so' can be an answer for 'ordinary' (I've seen this before). I'm not certain of the 'pretty' bit.
'repeated thus' is the wordplay.
'repeated' shows that letters should be duplicated.
'thus' becomes 'so' (synonyms).
'so' duplicated is 'SO-SO'.
'when' acts as a link.
Can you help me to learn more?
(Other definitions for so-so that I've seen before include "Native of Seville" , "Of middling quality" , "Tolerable, indifferent" , "Informally, only moderately good or well" , "Barely passable" .)