opportune

Concise Oxford English Dictionary © 2008 Oxford University Press:
opportune /ˈɒpətjuːn, ˌɒpəˈtjuːn/

▶adjective (of a time) especially convenient or appropriate.

■ appropriately timed.

– derivatives
opportunely adverb,
opportuneness noun.

word history: Opportune comes from Latin opportunus, denoting a favourable wind blowing towards the harbour (as opposed to one that would blow a ship out to sea), from ob- ‘in the direction of’ and portus ‘harbour’. From this developed the English sense ‘advantageous’ and also the noun opportunity. The Romans gave the name Portunus to the god who protected their harbours: from his name derives the negative word importunate, which originally meant ‘inconvenient’, and the related verb importune.