The use of cautious language when making a claim. There are many different ways in which language can be 'hedged'. These include using modal verbs such as 'may' 'might', should, could.  Using modal nouns such as 'probability' and 'assumption', using lexical verbs which denote a sense of caution i.e. 'assume' and 'indicate' and by using expressions which show a sense of caution or vagueness, i.e. 'it can be argued that' or 'it is likely to be the case that'. Hedging avoids you being challenged about what you write if you do not have evidence to back-up what you say.