Final answer:
In the sentence provided, 'reflection' implies that the defeat does not showcase any negative aspects of the players' performance, and 'criticism' is the closest synonym among the given choices.
Step-by-step explanation:
The sentence 'Yesterday's defeat was no reflection on our players; they did their very best' suggests that the word 'reflection' is used to mean that the defeat does not cast a negative light on the players' efforts or abilities. Out of the given options, 'criticism' would be the closest in meaning to 'reflection' in this context. The other options, 'indictment' and 'rebuke,' imply a much stronger disapproval. Hence, 'reflection' in this context denotes an observation or indication, and the idea is that the defeat should not be taken as a critique of the players' performance.