The word ironic comes from French ironique or late Latin ironicus, from Greek eironikos ‘dissembling, feigning ignorance’, from eironeia 'simulated ignorance', which came from the Greek eiron 'dissembler'.  

According to the Oxford English Dictionary (OED),  the adjective "ironic" first appeared in English in the early 1600s, with the earliest known evidence found in 1614 in the writings of William Cowper. 

The Oxford English Dictionary records its earliest use of the noun "irony" in 1502, in the book Ordynarye of Crysten Men.  The adverb "ironically" is first recorded in the 1530s and the adjective "ironical" in the 1570s. 

Examples of "ironic" used in a sentence: 
"At the most solemn moments he will flash a mocking smile or make an ironic remark." 
"People used to call me Mr Popularity at high school, but they were being ironic." 
"I find it ironic that after all the motorbike accidents he has had, he should, in the end, die in his bed." 
"Our sense of gratitude added a strangely ironic twist to the ordeal." 
"Or perhaps that was just a little ironic joke that went over my head." 
"It is ironic to think that, in later years, the police would require help themselves." 
"As part of Nana's torment, in a bitterly ironic twist, she has been taken to a nursing home with suspected dementia."