Caveat: I'm not a native Chinese.
I feel that in a certain context the "借一本词典给他" could be a bit ambiguous and could also mean "(You) Borrow a dictionary, (then) give it to him".
i.e., using "to lend" = "借给......" is always clearer than "借......给“.
although in practice (who has a dictionary to lend) and (who needs to borrow it) should already be known before making this statement, and therefore the ambiguity of 借 = "lend/borrow" is unlikely.