The following are clues to 18 six-letter words that must be filled into the following three linked word squares.

The clues are in no particular order, but just for fun, I tried to arrange them to tell a little story (which has no relevance to the puzzle's solution).

Overlapping portions of each square will obviously share the same letters.

• Acknowledge
• I
• Dissent
• Plagiarized
• Mocked
• Last
• Evil
• Plan
• Instructions
• Venerate
• Chamber
• Military instruments
• Deathly
• Word with fire or search
• Ball-drops
• Lands
• Do plural form clues yield plural form answers? Same tense etc? Jun 14 '16 at 19:55
• @JonathanAllan Yes. The clues are in the style of a crossword like the New York Times crossword, and generally follow the same conventions. Jun 14 '16 at 19:55

The eighteen words are (in the same order as in the question):

PRINCE (the artist later known as) Symbol
DEALER Buyer and seller
CREDIT Acknowledge
IODINE (the chemical element whose symbol is) I
UNREST Dissent
STOLEN Plagiarized
TEASED Mocked
ENDURE Last
SINFUL Evil
AGENDA Plan
RECIPE Instructions
ESTEEM Venerate
GROTTO Chamber
BUGLES Military instruments
LETHAL Deathly
ENGINE Word with fire or search
ERRORS Ball-drops (in Baseball, I believe)
ESTATE Lands

This gives the following grid:

B U G L E S
U N R E S T
G R O T T O
L E T H A L
E S T A T E A S E D
S T O L E N G I N E
        A G E N D A
        S I N F U L
        E N D U R E C I P E
        D E A L E R R O R S
                C R E D I T
                I O D I N E
                P R I N C E
                E S T E E M

• "Ball-drops" could also be figurative, as in, "I dropped the ball on that one." Jun 15 '16 at 11:29
• Amazing work, even with many of these, and many other options, I could not fit things together, I was going to write code to do it... (I would have thought lethal was deadly not deathly - I was thinking grisly, pallid, sallow, peaked etc...) Jun 17 '16 at 11:54
• @JonathanAllan: Thanks! To be frank, I did write a program and fed it as many guesses as I could find just to get a start. I had pallid, sickly and so on for deadly, too. I was pretty sure that it had to be TAFKAP or symbol instead of Prince; I had cavern and cavity, but not grotto; trader instead of dealer; copied and lifted instead of the (rather obvious) stolen. I didn't get unrest, estate and errors until very late. I got bugles and iodine from the outset, but coudn't go anywhere with them. So, yeah, it was quite tough, but fun. Jun 17 '16 at 12:17